[BrowserThread] Migration callers without full content:: namespace

Note to QA: This CL is purely mechanical and shouldn't be blamed
for future regressions on touched files.

This is a follow-up to https://chromium-review.googlesource.com/c/chromium/src/+/2211138
which already removed all usage using content::BrowserThread.

Hence this script now matches unqualified BrowserThread:: without
risking having "content::" be selected as "traits_before" by the regex
(ran on same revision as step #1).

content:: is now always added if outside namespace content {}
(deleting unused using content::BrowserThread; decls)

Script @ https://crbug.com/1026641#c92

(will TBR fdoray@ post-review for mechanical change)
TBR=fdoray@hchromium.org

AX-Relnotes: n/a.
Bug: 1026641
Change-Id: I51ae2f83eb17d19b54563fd9b4fc040d2aa0c948
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2212469
Commit-Queue: Gabriel Charette <gab@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772458}

android_webview/browser/aw_browser_process.cc

@@ -7,7 +7,6 @@
 #include "android_webview/browser/aw_browser_context.h"
 #include "base/base_paths_posix.h"
 #include "base/path_service.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -99,7 +98,7 @@ void AwBrowserProcess::CreateSafeBrowsingWhitelistManager() {
       base::ThreadPool::CreateSequencedTaskRunner(
           {base::MayBlock(), base::TaskPriority::BEST_EFFORT});
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner =
-      base::CreateSingleThreadTaskRunner({BrowserThread::IO});
+      content::GetIOThreadTaskRunner({});
   safe_browsing_whitelist_manager_ =
       std::make_unique<AwSafeBrowsingWhitelistManager>(background_task_runner,
                                                        io_task_runner);

android_webview/browser/aw_content_browser_client.cc

@@ -50,7 +50,6 @@
 #include "base/path_service.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "components/autofill/content/browser/content_autofill_driver_factory.h"
 #include "components/cdm/browser/cdm_message_filter_android.h"
@@ -226,8 +225,8 @@ void MaybeCreateSafeBrowsing(
   if (!render_process_host)
     return;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&safe_browsing::MojoSafeBrowsingImpl::MaybeCreate, rph_id,
                      resource_context, std::move(get_checker_delegate),
                      std::move(receiver)));
@@ -683,7 +682,7 @@ void AwContentBrowserClient::ExposeInterfacesToRenderer(
           base::BindRepeating(
               &AwContentBrowserClient::GetSafeBrowsingUrlCheckerDelegate,
               base::Unretained(this))),
-      base::CreateSingleThreadTaskRunner({BrowserThread::UI}));
+      content::GetUIThreadTaskRunner({}));
 
 #if BUILDFLAG(ENABLE_SPELLCHECK)
   auto create_spellcheck_host =
@@ -691,9 +690,8 @@ void AwContentBrowserClient::ExposeInterfacesToRenderer(
         mojo::MakeSelfOwnedReceiver(std::make_unique<SpellCheckHostImpl>(),
                                     std::move(receiver));
       };
-  registry->AddInterface(
-      base::BindRepeating(create_spellcheck_host),
-      base::CreateSingleThreadTaskRunner({BrowserThread::UI}));
+  registry->AddInterface(base::BindRepeating(create_spellcheck_host),
+                         content::GetUIThreadTaskRunner({}));
 #endif
 }
 

android_webview/browser/aw_contents.cc

@@ -58,7 +58,6 @@
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/supports_user_data.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/autofill/android/autofill_provider_android.h"
@@ -217,9 +216,7 @@ AwRenderProcessGoneDelegate* AwRenderProcessGoneDelegate::FromWebContents(
 
 AwContents::AwContents(std::unique_ptr<WebContents> web_contents)
     : content::WebContentsObserver(web_contents.get()),
-      browser_view_renderer_(
-          this,
-          base::CreateSingleThreadTaskRunner({BrowserThread::UI})),
+      browser_view_renderer_(this, content::GetUIThreadTaskRunner({})),
       web_contents_(std::move(web_contents)) {
   base::subtle::NoBarrier_AtomicIncrement(&g_instance_count, 1);
   icon_helper_.reset(new IconHelper(web_contents_.get()));

android_webview/browser/aw_contents_statics.cc

@@ -14,7 +14,6 @@
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
-#include "base/task/post_task.h"
 #include "components/google/core/common/google_util.h"
 #include "components/security_interstitials/core/urls.h"
 #include "components/version_info/version_info.h"
@@ -75,9 +74,8 @@ void JNI_AwContentsStatics_ClearClientCertPreferences(
     JNIEnv* env,
     const JavaParamRef<jobject>& callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  base::PostTaskAndReply(
-      FROM_HERE, {BrowserThread::IO},
-      base::BindOnce(&NotifyClientCertificatesChanged),
+  content::GetIOThreadTaskRunner({})->PostTaskAndReply(
+      FROM_HERE, base::BindOnce(&NotifyClientCertificatesChanged),
       base::BindOnce(&ClientCertificatesCleared,
                      ScopedJavaGlobalRef<jobject>(env, callback)));
 }

android_webview/browser/aw_http_auth_handler.cc

@@ -12,7 +12,6 @@
 #include "base/android/jni_string.h"
 #include "base/bind.h"
 #include "base/optional.h"
-#include "base/task/post_task.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
@@ -37,8 +36,8 @@ AwHttpAuthHandler::AwHttpAuthHandler(const net::AuthChallengeInfo& auth_info,
   http_auth_handler_.Reset(Java_AwHttpAuthHandler_create(
       env, reinterpret_cast<intptr_t>(this), first_auth_attempt));
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&AwHttpAuthHandler::Start, weak_factory_.GetWeakPtr()));
 }
 

android_webview/browser/aw_quota_manager_bridge.cc

@@ -15,7 +15,6 @@
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_refptr.h"
 #include "base/synchronization/waitable_event.h"
-#include "base/task/post_task.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/storage_partition.h"
@@ -87,8 +86,8 @@ GetOriginsTask::~GetOriginsTask() {}
 
 void GetOriginsTask::Run() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&QuotaManager::GetOriginsModifiedSince, quota_manager_,
                      blink::mojom::StorageType::kTemporary,
                      base::Time() /* Since beginning of time. */,
@@ -129,8 +128,8 @@ void GetOriginsTask::OnUsageAndQuotaObtained(
 void GetOriginsTask::CheckDone() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (num_callbacks_received_ == num_callbacks_to_wait_) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&GetOriginsTask::DoneOnUIThread, this));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&GetOriginsTask::DoneOnUIThread, this));
   } else if (num_callbacks_received_ > num_callbacks_to_wait_) {
     NOTREACHED();
   }
@@ -146,7 +145,7 @@ void RunOnUIThread(base::OnceClosure task) {
   if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     std::move(task).Run();
   } else {
-    base::PostTask(FROM_HERE, {BrowserThread::UI}, std::move(task));
+    content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE, std::move(task));
   }
 }
 
@@ -274,8 +273,8 @@ void OnUsageAndQuotaObtained(
     usage = 0;
     quota = 0;
   }
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(ui_callback), usage, quota));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(ui_callback), usage, quota));
 }
 
 }  // namespace
@@ -303,8 +302,8 @@ void AwQuotaManagerBridge::GetUsageAndQuotaForOriginOnUiThread(
                      weak_factory_.GetWeakPtr(), callback_id, is_quota);
 
   // TODO(crbug.com/889590): Use helper for url::Origin creation from string.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &QuotaManager::GetUsageAndQuota, GetQuotaManager(),
           url::Origin::Create(GURL(origin)),

android_webview/browser/aw_speech_recognition_manager_delegate.cc

@@ -8,7 +8,6 @@
 
 #include "base/bind.h"
 #include "base/macros.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_restrictions.h"
 #include "build/build_config.h"
 #include "components/prefs/pref_service.h"
@@ -82,8 +81,8 @@ void AwSpeechRecognitionManagerDelegate::CheckRecognitionIsAllowed(
 
   // Check that the render frame type is appropriate, and whether or not we
   // need to request permission from the user.
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&CheckRenderFrameType, std::move(callback),
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&CheckRenderFrameType, std::move(callback),
                                 render_process_id, render_frame_id));
 }
 
@@ -107,8 +106,8 @@ void AwSpeechRecognitionManagerDelegate::CheckRenderFrameType(
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // Regular tab contents.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(std::move(callback), true /* check_permission */,
                      true /* allowed */));
 }

android_webview/browser/gfx/aw_draw_fn_impl.cc

@@ -12,7 +12,6 @@
 #include "android_webview/public/browser/draw_gl.h"
 #include "base/android/android_hardware_buffer_compat.h"
 #include "base/android/scoped_hardware_buffer_fence_sync.h"
-#include "base/task/post_task.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -204,8 +203,7 @@ static void JNI_AwDrawFnImpl_SetDrawFnFunctionTable(JNIEnv* env,
 AwDrawFnImpl::AwDrawFnImpl()
     : is_interop_mode_(!base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kWebViewEnableVulkan)),
-      render_thread_manager_(
-          base::CreateSingleThreadTaskRunner({BrowserThread::UI})) {
+      render_thread_manager_(content::GetUIThreadTaskRunner({})) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(g_draw_fn_function_table);
 

android_webview/browser/gfx/aw_gl_functor.cc

@@ -7,7 +7,6 @@
 #include "android_webview/browser_jni_headers/AwGLFunctor_jni.h"
 #include "android_webview/public/browser/draw_gl.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 
@@ -36,8 +35,7 @@ int g_instance_count = 0;
 
 AwGLFunctor::AwGLFunctor(const JavaObjectWeakGlobalRef& java_ref)
     : java_ref_(java_ref),
-      render_thread_manager_(
-          base::CreateSingleThreadTaskRunner({BrowserThread::UI})) {
+      render_thread_manager_(content::GetUIThreadTaskRunner({})) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   ++g_instance_count;
 }

android_webview/browser/safe_browsing/aw_safe_browsing_ui_manager.cc

@@ -17,7 +17,6 @@
 #include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
-#include "base/task/post_task.h"
 #include "components/safe_browsing/content/base_ui_manager.h"
 #include "components/safe_browsing/core/browser/safe_browsing_network_context.h"
 #include "components/safe_browsing/core/common/safebrowsing_constants.h"
@@ -94,8 +93,8 @@ scoped_refptr<network::SharedURLLoaderFactory>
 AwSafeBrowsingUIManager::GetURLLoaderFactoryOnIOThread() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (!shared_url_loader_factory_on_io_) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&AwSafeBrowsingUIManager::CreateURLLoaderFactoryForIO,
                        this,
                        url_loader_factory_on_io_.BindNewPipeAndPassReceiver()));

apps/launcher.cc

@@ -16,7 +16,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/task/task_traits.h"
 #include "base/task/thread_pool.h"
 #include "components/services/app_service/public/cpp/file_handler_info.h"
@@ -175,16 +174,16 @@ class PlatformAppPathLauncher
          it != entry_paths_.end(); ++it) {
       if (!DoMakePathAbsolute(current_directory, &*it)) {
         LOG(WARNING) << "Cannot make absolute path from " << it->value();
-        base::PostTask(
-            FROM_HERE, {BrowserThread::UI},
+        content::GetUIThreadTaskRunner({})->PostTask(
+            FROM_HERE,
             base::BindOnce(&PlatformAppPathLauncher::LaunchWithBasicData,
                            this));
         return;
       }
     }
 
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&PlatformAppPathLauncher::Launch, this));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&PlatformAppPathLauncher::Launch, this));
   }
 
   void OnFilesValid(std::unique_ptr<std::set<base::FilePath>> directory_paths) {

chrome/browser/after_startup_task_utils.cc

@@ -17,7 +17,6 @@
 #include "base/sequence_checker.h"
 #include "base/sequenced_task_runner.h"
 #include "base/synchronization/atomic_flag.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -103,8 +102,8 @@ void QueueTask(std::unique_ptr<AfterStartupTask> queued_task) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     // Posted with USER_VISIBLE priority to avoid this becoming an after startup
     // task itself.
-    base::PostTask(FROM_HERE,
-                   {BrowserThread::UI, base::TaskPriority::USER_VISIBLE},
+    content::GetUIThreadTaskRunner({base::TaskPriority::USER_VISIBLE})
+        ->PostTask(FROM_HERE,
                    base::BindOnce(QueueTask, std::move(queued_task)));
     return;
   }
@@ -227,10 +226,11 @@ void StartupObserver::Start() {
   delay = base::TimeDelta::FromMinutes(kLongerDelayMins);
 #endif  // !defined(OS_ANDROID)
 
-  base::PostDelayedTask(FROM_HERE, {BrowserThread::UI},
-                        base::BindOnce(&StartupObserver::OnFailsafeTimeout,
-                                       weak_factory_.GetWeakPtr()),
-                        delay);
+  content::GetUIThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE,
+      base::BindOnce(&StartupObserver::OnFailsafeTimeout,
+                     weak_factory_.GetWeakPtr()),
+      delay);
 }
 
 }  // namespace

chrome/browser/android/bookmarks/partner_bookmarks_reader.cc

@@ -9,7 +9,6 @@
 #include "base/bind.h"
 #include "base/guid.h"
 #include "base/logging.h"
-#include "base/task/post_task.h"
 #include "chrome/android/chrome_jni_headers/PartnerBookmarksReader_jni.h"
 #include "chrome/browser/android/bookmarks/partner_bookmarks_shim.h"
 #include "chrome/browser/browser_process.h"
@@ -90,8 +89,8 @@ void PrepareAndSetFavicon(jbyte* icon_bytes,
 
   base::WaitableEvent event(base::WaitableEvent::ResetPolicy::AUTOMATIC,
                             base::WaitableEvent::InitialState::NOT_SIGNALED);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&SetFaviconCallback, profile, node->url(),
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&SetFaviconCallback, profile, node->url(),
                                 fake_icon_url, image_data, icon_type, &event));
   // TODO(aruslan): http://b/6397072 If possible - avoid using favicon service
   event.Wait();
@@ -228,8 +227,8 @@ void PartnerBookmarksReader::GetFavicon(const GURL& page_url,
                                         bool fallback_to_server,
                                         int desired_favicon_size_px,
                                         FaviconFetchedCallback callback) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&PartnerBookmarksReader::GetFaviconImpl,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&PartnerBookmarksReader::GetFaviconImpl,
                                 base::Unretained(this), page_url, profile,
                                 fallback_to_server, desired_favicon_size_px,
                                 std::move(callback)));

chrome/browser/android/feedback/process_id_feedback_source.cc

@@ -4,7 +4,6 @@
 
 #include "chrome/browser/android/feedback/process_id_feedback_source.h"
 
-#include "base/task/post_task.h"
 #include "chrome/android/chrome_jni_headers/ProcessIdFeedbackSource_jni.h"
 #include "content/public/browser/browser_task_traits.h"
 
@@ -54,8 +53,8 @@ void ProcessIdFeedbackSource::PrepareProcessIds() {
     process_ids_[content::PROCESS_TYPE_RENDERER].push_back(
         host->GetProcess().Pid());
   }
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ProcessIdFeedbackSource::PrepareProcessIdsOnIOThread,
                      this));
 }
@@ -67,8 +66,8 @@ void ProcessIdFeedbackSource::PrepareProcessIdsOnIOThread() {
     process_ids_[iter.GetData().process_type].push_back(
         iter.GetData().GetProcess().Handle());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ProcessIdFeedbackSource::PrepareCompleted, this));
 }
 

chrome/browser/apps/platform_apps/api/sync_file_system/sync_file_system_api.cc

@@ -12,7 +12,6 @@
 #include "base/check_op.h"
 #include "base/notreached.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/apps/platform_apps/api/sync_file_system/extension_sync_event_observer.h"
 #include "chrome/browser/apps/platform_apps/api/sync_file_system/sync_file_system_api_helpers.h"
 #include "chrome/browser/profiles/profile.h"
@@ -104,8 +103,8 @@ SyncFileSystemDeleteFileSystemFunction::Run() {
   storage::FileSystemURL file_system_url(
       file_system_context->CrackURL(GURL(url)));
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       BindOnce(
           &storage::FileSystemContext::DeleteFileSystem, file_system_context,
           url::Origin::Create(source_url().GetOrigin()), file_system_url.type(),
@@ -119,8 +118,8 @@ void SyncFileSystemDeleteFileSystemFunction::DidDeleteFileSystem(
   // Repost to switch from IO thread to UI thread for SendResponse().
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         BindOnce(&SyncFileSystemDeleteFileSystemFunction::DidDeleteFileSystem,
                  this, error));
     return;
@@ -150,8 +149,8 @@ SyncFileSystemRequestFileSystemFunction::Run() {
 
   // Initializes sync context for this extension and continue to open
   // a new file system.
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 BindOnce(&storage::FileSystemContext::OpenFileSystem,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, BindOnce(&storage::FileSystemContext::OpenFileSystem,
                           GetFileSystemContext(),
                           url::Origin::Create(source_url().GetOrigin()),
                           storage::kFileSystemTypeSyncable,
@@ -175,8 +174,8 @@ void SyncFileSystemRequestFileSystemFunction::DidOpenFileSystem(
   // Repost to switch from IO thread to UI thread for SendResponse().
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         BindOnce(&SyncFileSystemRequestFileSystemFunction::DidOpenFileSystem,
                  this, root_url, file_system_name, error));
     return;
@@ -333,8 +332,8 @@ SyncFileSystemGetUsageAndQuotaFunction::Run() {
           browser_context(), render_frame_host()->GetSiteInstance())
           ->GetQuotaManager();
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       BindOnce(
           &storage::QuotaManager::GetUsageAndQuotaForWebApps, quota_manager,
           url::Origin::Create(source_url()),
@@ -352,8 +351,8 @@ void SyncFileSystemGetUsageAndQuotaFunction::DidGetUsageAndQuota(
   // Repost to switch from IO thread to UI thread for SendResponse().
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         BindOnce(&SyncFileSystemGetUsageAndQuotaFunction::DidGetUsageAndQuota,
                  this, status, usage, quota));
     return;

chrome/browser/background/background_mode_manager_mac.mm

@@ -6,7 +6,6 @@
 #include "base/command_line.h"
 #include "base/mac/mac_util.h"
 #include "base/sequenced_task_runner.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/scoped_blocking_call.h"
 #include "chrome/browser/background/background_mode_manager.h"
@@ -47,8 +46,8 @@ void CheckForUserRemovedLoginItemOnWorkerThread() {
                                                 base::BlockingType::MAY_BLOCK);
   if (!base::mac::CheckLoginItemStatus(NULL)) {
     // There's no LoginItem, so set the kUserRemovedLoginItem pref.
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(SetUserRemovedLoginItemPrefOnUIThread));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(SetUserRemovedLoginItemPrefOnUIThread));
   }
 }
 
@@ -64,8 +63,8 @@ void EnableLaunchOnStartupOnWorkerThread(bool need_migration) {
       if (is_hidden) {
       // We already have a hidden login item, so set the kChromeCreatedLoginItem
       // flag.
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(SetCreatedLoginItemPrefOnUIThread));
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(SetCreatedLoginItemPrefOnUIThread));
       }
       // LoginItem already exists - just exit.
       return;
@@ -80,8 +79,8 @@ void EnableLaunchOnStartupOnWorkerThread(bool need_migration) {
     // before our callback is run, but the user can manually disable
     // "Open At Login" via the dock if this happens.
     base::mac::AddToLoginItems(true);  // Hide on startup.
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(SetCreatedLoginItemPrefOnUIThread));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(SetCreatedLoginItemPrefOnUIThread));
   }
 }
 

chrome/browser/browser_process_impl.cc

@@ -25,7 +25,6 @@
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/waitable_event.h"
-#include "base/task/post_task.h"
 #include "base/task/task_traits.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread.h"
@@ -562,8 +561,8 @@ void RequestProxyResolvingSocketFactoryOnUIThread(
 void RequestProxyResolvingSocketFactory(
     mojo::PendingReceiver<network::mojom::ProxyResolvingSocketFactory>
         receiver) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&RequestProxyResolvingSocketFactoryOnUIThread,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&RequestProxyResolvingSocketFactoryOnUIThread,
                                 std::move(receiver)));
 }
 #endif

chrome/browser/browsing_data/browsing_data_media_license_helper.cc

@@ -11,7 +11,6 @@
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/sequenced_task_runner.h"
-#include "base/task/post_task.h"
 #include "components/browsing_data/content/browsing_data_helper.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -114,8 +113,8 @@ void BrowsingDataMediaLicenseHelperImpl::FetchMediaLicenseInfoOnFileTaskRunner(
         MediaLicenseInfo(origin.GetURL(), size, last_modified_time));
   }
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), result));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 void BrowsingDataMediaLicenseHelperImpl::

chrome/browser/browsing_data/browsing_data_quota_helper.cc

@@ -5,12 +5,9 @@
 #include "chrome/browser/browsing_data/browsing_data_quota_helper.h"
 
 #include "base/location.h"
-#include "base/task/post_task.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 
-using content::BrowserThread;
-
 BrowsingDataQuotaHelper::QuotaInfo::QuotaInfo() {}
 
 BrowsingDataQuotaHelper::QuotaInfo::QuotaInfo(const std::string& host)
@@ -30,7 +27,7 @@ BrowsingDataQuotaHelper::QuotaInfo::~QuotaInfo() {}
 // static
 void BrowsingDataQuotaHelperDeleter::Destruct(
     const BrowsingDataQuotaHelper* helper) {
-  base::DeleteSoon(FROM_HERE, {BrowserThread::IO}, helper);
+  content::GetIOThreadTaskRunner({})->DeleteSoon(FROM_HERE, helper);
 }
 
 BrowsingDataQuotaHelper::BrowsingDataQuotaHelper() {}

chrome/browser/browsing_data/browsing_data_quota_helper_impl.cc

@@ -12,12 +12,12 @@
 #include "base/check_op.h"
 #include "base/notreached.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/url_constants.h"
 #include "components/browsing_data/content/browsing_data_helper.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_task_traits.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/storage_partition.h"
 #include "storage/browser/quota/quota_manager.h"
 #include "third_party/blink/public/mojom/quota/quota_types.mojom.h"
@@ -37,16 +37,16 @@ void BrowsingDataQuotaHelperImpl::StartFetching(FetchResultCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(!callback.is_null());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&BrowsingDataQuotaHelperImpl::FetchQuotaInfoOnIOThread,
                      this, std::move(callback)));
 }
 
 void BrowsingDataQuotaHelperImpl::RevokeHostQuota(const std::string& host) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&BrowsingDataQuotaHelperImpl::RevokeHostQuotaOnIOThread,
                      this, host));
 }
@@ -161,8 +161,8 @@ void BrowsingDataQuotaHelperImpl::OnGetHostsUsageComplete(
     result.push_back(info);
   }
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), result));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 void BrowsingDataQuotaHelperImpl::RevokeHostQuotaOnIOThread(

chrome/browser/browsing_data/browsing_data_quota_helper_unittest.cc

@@ -10,9 +10,9 @@
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/weak_ptr.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/browsing_data/browsing_data_quota_helper_impl.h"
 #include "content/public/browser/browser_task_traits.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/test/browser_task_environment.h"
 #include "content/public/test/test_utils.h"
 #include "storage/browser/quota/quota_manager.h"
@@ -21,7 +21,6 @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 using blink::mojom::StorageType;
-using content::BrowserThread;
 using storage::MockOriginData;
 using storage::MockQuotaClient;
 
@@ -37,9 +36,8 @@ class BrowsingDataQuotaHelperTest : public testing::Test {
   void SetUp() override {
     EXPECT_TRUE(dir_.CreateUniqueTempDir());
     quota_manager_ = base::MakeRefCounted<storage::QuotaManager>(
-        false, dir_.GetPath(),
-        base::CreateSingleThreadTaskRunner({BrowserThread::IO}).get(), nullptr,
-        storage::GetQuotaSettingsFunc());
+        false, dir_.GetPath(), content::GetIOThreadTaskRunner({}).get(),
+        nullptr, storage::GetQuotaSettingsFunc());
     helper_ = new BrowsingDataQuotaHelperImpl(quota_manager_.get());
   }
 

chrome/browser/browsing_data/chrome_browsing_data_remover_delegate.cc

@@ -19,7 +19,6 @@
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
@@ -171,7 +170,7 @@ const base::TimeDelta kSlowTaskTimeout = base::TimeDelta::FromSeconds(180);
 // Generic functions but currently only used when ENABLE_NACL.
 #if BUILDFLAG(ENABLE_NACL)
 void UIThreadTrampolineHelper(base::OnceClosure callback) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI}, std::move(callback));
+  content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE, std::move(callback));
 }
 
 // Convenience method to create a callback that can be run on any thread and
@@ -343,9 +342,8 @@ void ChromeBrowsingDataRemoverDelegate::RemoveEmbedderData(
   slow_pending_tasks_closure_.Reset(base::BindRepeating(
       &ChromeBrowsingDataRemoverDelegate::RecordUnfinishedSubTasks,
       weak_ptr_factory_.GetWeakPtr()));
-  base::PostDelayedTask(FROM_HERE, {BrowserThread::UI},
-                        slow_pending_tasks_closure_.callback(),
-                        kSlowTaskTimeout);
+  content::GetUIThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE, slow_pending_tasks_closure_.callback(), kSlowTaskTimeout);
 
   // Embedder-defined DOM-accessible storage currently contains only
   // one datatype, which is the durable storage permission.
@@ -929,13 +927,13 @@ void ChromeBrowsingDataRemoverDelegate::RemoveEmbedderData(
     }
 
 #if BUILDFLAG(ENABLE_NACL)
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&ClearNaClCacheOnIOThread,
                        UIThreadTrampoline(CreateTaskCompletionClosure(
                            TracingDataType::kNaclCache))));
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&ClearPnaclCacheOnIOThread, delete_begin_, delete_end_,
                        UIThreadTrampoline(CreateTaskCompletionClosure(
                            TracingDataType::kPnaclCache))));

chrome/browser/browsing_data/counters/site_data_counting_helper.cc

@@ -5,7 +5,6 @@
 #include "chrome/browser/browsing_data/counters/site_data_counting_helper.h"
 
 #include "base/bind.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "chrome/browser/browsing_data/browsing_data_flash_lso_helper.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
@@ -74,8 +73,8 @@ void SiteDataCountingHelper::CountAndDestroySelfWhenFinished() {
         blink::mojom::StorageType::kSyncable};
     for (auto type : types) {
       tasks_ += 1;
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&storage::QuotaManager::GetOriginsModifiedSince,
                          quota_manager, type, begin_, origins_callback));
     }
@@ -165,8 +164,8 @@ void SiteDataCountingHelper::GetCookiesCallback(
       origins.push_back(url);
     }
   }
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&SiteDataCountingHelper::Done,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&SiteDataCountingHelper::Done,
                                 base::Unretained(this), origins));
 }
 
@@ -178,8 +177,8 @@ void SiteDataCountingHelper::GetQuotaOriginsCallback(
   urls.resize(origins.size());
   for (const url::Origin& origin : origins)
     urls.push_back(origin.GetURL());
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&SiteDataCountingHelper::Done,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&SiteDataCountingHelper::Done,
                                 base::Unretained(this), std::move(urls)));
 }
 

chrome/browser/captive_portal/captive_portal_browsertest.cc

@@ -24,7 +24,6 @@
 #include "base/sequence_checker.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/test/bind_test_util.h"
 #include "base/values.h"
 #include "build/build_config.h"
@@ -781,8 +780,8 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
     if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
       SetNumJobsToWaitForOnInterceptorThread(num_jobs);
     } else {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(
               &CaptivePortalBrowserTest::SetNumJobsToWaitForOnInterceptorThread,
               base::Unretained(this), num_jobs));
@@ -800,8 +799,8 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
 
     int num_ongoing_jobs = static_cast<int>(ongoing_mock_requests_.size());
     if (num_ongoing_jobs == num_jobs) {
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(&CaptivePortalBrowserTest::QuitRunLoop,
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&CaptivePortalBrowserTest::QuitRunLoop,
                                     base::Unretained(this)));
       return;
     }
@@ -819,8 +818,8 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
                 int error,
                 net::ResolveErrorInfo resolve_error_info) {
     if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(&CaptivePortalBrowserTest::FailJobs,
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&CaptivePortalBrowserTest::FailJobs,
                                     base::Unretained(this), expected_num_jobs,
                                     error, resolve_error_info));
       return;
@@ -841,8 +840,8 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
   void FailJobsWithCertError(int expected_num_jobs,
                              const net::SSLInfo& ssl_info) {
     if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&CaptivePortalBrowserTest::FailJobsWithCertError,
                          base::Unretained(this), expected_num_jobs, ssl_info));
       return;
@@ -861,8 +860,8 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
     EXPECT_EQ(expected_num_jobs,
               static_cast<int>(ongoing_mock_requests_.size()));
     for (auto& job : ongoing_mock_requests_) {
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(&CaptivePortalBrowserTest::CreateLoader,
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&CaptivePortalBrowserTest::CreateLoader,
                                     base::Unretained(this), std::move(job)));
     }
     ongoing_mock_requests_.clear();
@@ -882,8 +881,8 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
   // behaves just as in FailJobs.
   void AbandonJobs(int expected_num_jobs) {
     if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(&CaptivePortalBrowserTest::AbandonJobs,
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&CaptivePortalBrowserTest::AbandonJobs,
                                     base::Unretained(this), expected_num_jobs));
       return;
     }
@@ -1036,8 +1035,8 @@ bool CaptivePortalBrowserTest::OnIntercept(
         if (num_jobs_to_wait_for_ ==
             static_cast<int>(ongoing_mock_requests_.size())) {
           num_jobs_to_wait_for_ = 0;
-          base::PostTask(FROM_HERE, {BrowserThread::UI},
-                         base::BindOnce(&CaptivePortalBrowserTest::QuitRunLoop,
+          content::GetUIThreadTaskRunner({})->PostTask(
+              FROM_HERE, base::BindOnce(&CaptivePortalBrowserTest::QuitRunLoop,
                                         base::Unretained(this)));
         }
       }

chrome/browser/certificate_manager_model.cc

@@ -14,7 +14,6 @@
 #include "base/sequence_checker.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "chrome/browser/net/nss_context.h"
 #include "chrome/browser/ui/crypto_module_password_dialog_nss.h"
@@ -497,8 +496,8 @@ void CertificateManagerModel::Create(
       certificate_provider_service->CreateCertificateProvider();
 #endif
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CertificateManagerModel::GetCertDBOnIOThread,
                      std::move(params), browser_context->GetResourceContext(),
                      observer, std::move(callback)));
@@ -699,8 +698,8 @@ void CertificateManagerModel::DidGetCertDBOnIOThread(
 #if defined(OS_CHROMEOS)
   is_tpm_available = crypto::IsTPMTokenEnabledForNSS();
 #endif
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CertificateManagerModel::DidGetCertDBOnUIThread,
                      std::move(params), observer, std::move(callback), cert_db,
                      is_user_db_available, is_tpm_available));

chrome/browser/chrome_browser_main.cc

@@ -37,7 +37,6 @@
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/system/sys_info.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/hang_watcher.h"
 #include "base/threading/platform_thread.h"
@@ -308,8 +307,6 @@
 #include "components/spellcheck/common/spellcheck_features.h"
 #endif  // BUILDFLAG(USE_WIN_HYBRID_SPELLCHECKER)
 
-using content::BrowserThread;
-
 namespace {
 
 #if !defined(OS_ANDROID)
@@ -1013,14 +1010,14 @@ void ChromeBrowserMainParts::PostCreateThreads() {
   // BrowserMainLoop::InitializeMainThread(). PostCreateThreads is preferred to
   // BrowserThreadsStarted as it matches the PreCreateThreads and CreateThreads
   // stages.
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&ThreadProfiler::StartOnChildThread,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&ThreadProfiler::StartOnChildThread,
                                 metrics::CallStackProfileParams::IO_THREAD));
 // Sampling multiple threads might cause overhead on Android and we don't want
 // to enable it unless the data is needed.
 #if !defined(OS_ANDROID)
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&tracing::TracingSamplerProfiler::CreateOnChildThread));
 #endif
 
@@ -1109,8 +1106,8 @@ void ChromeBrowserMainParts::PostBrowserStart() {
 #endif  // !defined(OS_ANDROID)
   // Set up a task to delete old WebRTC log files for all profiles. Use a delay
   // to reduce the impact on startup time.
-  base::PostDelayedTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE,
       base::BindOnce(&WebRtcLogUtil::DeleteOldWebRtcLogFilesForAllProfiles),
       base::TimeDelta::FromMinutes(1));
 
@@ -1143,7 +1140,7 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
 
   // Can't be in SetupFieldTrials() because it needs a task runner.
   blink::MemoryAblationExperiment::MaybeStart(
-      base::CreateSingleThreadTaskRunner({BrowserThread::IO}));
+      content::GetIOThreadTaskRunner({}));
 
 #if defined(OS_WIN)
   // Windows parental controls calls can be slow, so we do an early init here
@@ -1558,8 +1555,8 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
 #endif
 
 #if BUILDFLAG(ENABLE_NACL)
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(nacl::NaClProcessHost::EarlyStartup));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(nacl::NaClProcessHost::EarlyStartup));
 #endif  // BUILDFLAG(ENABLE_NACL)
 
   // Make sure initial prefs are recorded

chrome/browser/chrome_browser_main_posix.cc

@@ -17,7 +17,6 @@
 #include "base/check_op.h"
 #include "base/macros.h"
 #include "base/notreached.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "chrome/app/shutdown_signal_handlers_posix.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
@@ -115,8 +114,8 @@ void ExitHandler::OnSessionRestoreDone(int /* num_tabs */) {
     // At this point the message loop may not be running (meaning we haven't
     // gotten through browser startup, but are close). Post the task to at which
     // point the message loop is running.
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&ExitHandler::Exit));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&ExitHandler::Exit));
     delete this;
   }
 }
@@ -161,7 +160,7 @@ void ChromeBrowserMainPartsPosix::PostMainMessageLoopStart() {
   // Exit in response to SIGINT, SIGTERM, etc.
   InstallShutdownSignalHandlers(
       base::BindOnce(&ExitHandler::ExitWhenPossibleOnUIThread),
-      base::CreateSingleThreadTaskRunner({BrowserThread::UI}));
+      content::GetUIThreadTaskRunner({}));
 }
 
 void ChromeBrowserMainPartsPosix::ShowMissingLocaleMessageBox() {

chrome/browser/chrome_content_browser_client.cc

@@ -33,7 +33,6 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/system/sys_info.h"
-#include "base/task/post_task.h"
 #include "base/threading/sequenced_task_runner_handle.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
@@ -1293,8 +1292,8 @@ void ChromeContentBrowserClient::SetApplicationLocale(
   // the IO thread.
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&SetApplicationLocaleOnIOThread, locale));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&SetApplicationLocaleOnIOThread, locale));
 }
 
 std::unique_ptr<content::BrowserMainParts>
@@ -4916,8 +4915,8 @@ bool ChromeContentBrowserClient::HandleExternalProtocol(
     return false;
 #endif  // defined(ANDROID)
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&LaunchURL, url, std::move(web_contents_getter),
                      page_transition, has_user_gesture, initiating_origin));
   return true;

chrome/browser/chrome_plugin_browsertest.cc

@@ -15,7 +15,6 @@
 #include "base/process/process.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "build/branding_buildflags.h"
 #include "build/build_config.h"
 #include "chrome/browser/plugins/plugin_prefs.h"
@@ -45,8 +44,6 @@
 #include "ui/aura/window_tree_host.h"
 #endif
 
-using content::BrowserThread;
-
 namespace {
 
 class CallbackBarrier : public base::RefCountedThreadSafe<CallbackBarrier> {
@@ -114,8 +111,8 @@ class ChromePluginTest : public InProcessBrowserTest {
   static void CrashFlash() {
     scoped_refptr<content::MessageLoopRunner> runner =
         new content::MessageLoopRunner;
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(&CrashFlashInternal, runner->QuitClosure()));
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&CrashFlashInternal, runner->QuitClosure()));
     runner->Run();
   }
 
@@ -143,8 +140,8 @@ class ChromePluginTest : public InProcessBrowserTest {
     int actual = 0;
     scoped_refptr<content::MessageLoopRunner> runner =
         new content::MessageLoopRunner;
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&CountPluginProcesses, &actual, runner->QuitClosure()));
     runner->Run();
     ASSERT_EQ(expected, actual);
@@ -160,7 +157,8 @@ class ChromePluginTest : public InProcessBrowserTest {
       found = true;
     }
     ASSERT_TRUE(found) << "Didn't find Flash process!";
-    base::PostTask(FROM_HERE, {BrowserThread::UI}, std::move(quit_task));
+    content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE,
+                                                 std::move(quit_task));
   }
 
   static void GetPluginsInfoCallback(
@@ -176,7 +174,8 @@ class ChromePluginTest : public InProcessBrowserTest {
       if (iter.GetData().process_type == content::PROCESS_TYPE_PPAPI_PLUGIN)
         (*count)++;
     }
-    base::PostTask(FROM_HERE, {BrowserThread::UI}, std::move(quit_task));
+    content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE,
+                                                 std::move(quit_task));
   }
 };
 

chrome/browser/chromeos/accessibility/accessibility_manager.cc

@@ -33,7 +33,6 @@
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "base/values.h"
 #include "chrome/browser/accessibility/accessibility_extension_api.h"
 #include "chrome/browser/browser_process.h"
@@ -91,7 +90,6 @@
 #include "ui/views/widget/widget_observer.h"
 #include "url/gurl.h"
 
-using content::BrowserThread;
 using extensions::api::braille_display_private::BrailleController;
 using extensions::api::braille_display_private::DisplayState;
 using extensions::api::braille_display_private::KeyEvent;
@@ -1032,8 +1030,8 @@ void AccessibilityManager::CheckBrailleState() {
   BrailleController* braille_controller = GetBrailleController();
   if (!scoped_braille_observer_.IsObserving(braille_controller))
     scoped_braille_observer_.Add(braille_controller);
-  base::PostTaskAndReplyWithResult(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTaskAndReplyWithResult(
+      FROM_HERE,
       base::BindOnce(&BrailleController::GetDisplayState,
                      base::Unretained(braille_controller)),
       base::BindOnce(&AccessibilityManager::ReceiveBrailleDisplayState,

chrome/browser/chromeos/app_mode/kiosk_app_data.cc

@@ -12,7 +12,6 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted_memory.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
@@ -156,8 +155,8 @@ class KioskAppData::CrxLoader : public extensions::SandboxedUnpackerClient {
                    << temp_dir_.GetPath().value();
     }
 
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&CrxLoader::NotifyFinishedOnUIThread, this));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&CrxLoader::NotifyFinishedOnUIThread, this));
   }
 
   void NotifyFinishedOnUIThread() {

chrome/browser/chromeos/app_mode/kiosk_app_icon_loader.cc

@@ -10,7 +10,6 @@
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/sequenced_task_runner.h"
-#include "base/task/post_task.h"
 #include "base/task/task_traits.h"
 #include "base/task/thread_pool.h"
 #include "chrome/browser/image_decoder/image_decoder.h"
@@ -30,15 +29,15 @@ class IconImageRequest : public ImageDecoder::ImageRequest {
   void OnImageDecoded(const SkBitmap& decoded_image) override {
     gfx::ImageSkia image = gfx::ImageSkia::CreateFrom1xBitmap(decoded_image);
     image.MakeThreadSafe();
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(result_callback_, image));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(result_callback_, image));
     delete this;
   }
 
   void OnDecodeImageFailed() override {
     LOG(ERROR) << "Failed to decode icon image.";
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(result_callback_, base::Optional<gfx::ImageSkia>()));
     delete this;
   }
@@ -57,8 +56,8 @@ void LoadOnBlockingPool(
   std::string data;
   if (!base::ReadFileToString(base::FilePath(icon_path), &data)) {
     LOG(ERROR) << "Failed to read icon file.";
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(result_callback, base::Optional<gfx::ImageSkia>()));
     return;
   }

chrome/browser/chromeos/arc/file_system_watcher/arc_file_system_watcher_service.cc

@@ -20,7 +20,6 @@
 #include "base/sequence_checker.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
-#include "base/task/post_task.h"
 #include "base/task/task_traits.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/sequenced_task_runner_handle.h"
@@ -288,8 +287,8 @@ void ArcFileSystemWatcherService::FileSystemWatcher::OnBuildTimestampMap(
   for (size_t i = 0; i < changed_paths.size(); ++i) {
     string_paths[i] = changed_paths[i].value();
   }
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(callback_, std::move(string_paths)));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(callback_, std::move(string_paths)));
   if (last_notify_time_ > snapshot_time)
     DelayBuildTimestampMap();
   else

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_async_file_util.cc

@@ -12,7 +12,6 @@
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/notreached.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_map.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_util.h"
@@ -35,8 +34,8 @@ void OnGetFileInfoOnUIThread(
     base::File::Error result,
     const base::File::Info& info) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result, info));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result, info));
 }
 
 void OnReadDirectoryOnUIThread(
@@ -54,8 +53,8 @@ void OnReadDirectoryOnUIThread(
                              : filesystem::mojom::FsFileType::REGULAR_FILE);
   }
 
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result, entries,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result, entries,
                                 false /* has_more */));
 }
 
@@ -70,16 +69,16 @@ void OnCreateFileOnUIThread(
   } else if (result == base::File::FILE_ERROR_EXISTS) {
     result_to_report = base::File::FILE_OK;
   }
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(std::move(callback), result_to_report, created));
 }
 
 void OnStatusCallbackOnUIThread(storage::AsyncFileUtil::StatusCallback callback,
                                 base::File::Error result) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 void GetFileInfoOnUIThread(
@@ -308,8 +307,8 @@ void ArcDocumentsProviderAsyncFileUtil::EnsureFileExists(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, url.type());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CreateFileOnUIThread, url, std::move(callback)));
 }
 
@@ -327,8 +326,8 @@ void ArcDocumentsProviderAsyncFileUtil::CreateDirectory(
   // directory already exists at |url| for simpler ArcDocumentsProviderRoot
   // implementation. Chances of this case are small, since Files app
   // de-duplicate the new directory name to avoid conflicting with existing one.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CreateDirectoryOnUIThread, url, std::move(callback)));
 }
 
@@ -340,8 +339,8 @@ void ArcDocumentsProviderAsyncFileUtil::GetFileInfo(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, url.type());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&GetFileInfoOnUIThread, url, fields, std::move(callback)));
 }
 
@@ -352,8 +351,8 @@ void ArcDocumentsProviderAsyncFileUtil::ReadDirectory(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, url.type());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ReadDirectoryOnUIThread, url, std::move(callback)));
 }
 
@@ -393,8 +392,8 @@ void ArcDocumentsProviderAsyncFileUtil::CopyFileLocal(
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, src_url.type());
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, dest_url.type());
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&CopyFileLocalOnUIThread, src_url, dest_url,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&CopyFileLocalOnUIThread, src_url, dest_url,
                                 std::move(callback)));
 }
 
@@ -408,8 +407,8 @@ void ArcDocumentsProviderAsyncFileUtil::MoveFileLocal(
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, src_url.type());
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, dest_url.type());
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&MoveFileLocalOnUIThread, src_url, dest_url,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&MoveFileLocalOnUIThread, src_url, dest_url,
                                 std::move(callback)));
 }
 
@@ -431,8 +430,8 @@ void ArcDocumentsProviderAsyncFileUtil::DeleteFile(
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, url.type());
 
   // TODO(fukino): Report an error if the document at |url| is not a file.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DeleteFileOnUIThread, url, std::move(callback)));
 }
 
@@ -446,8 +445,8 @@ void ArcDocumentsProviderAsyncFileUtil::DeleteDirectory(
   // TODO(fukino): Report an error if the document at |url| is not a directory.
   // TODO(fukino): Report an error if the document at |url| is a directory which
   // is not empty.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DeleteFileOnUIThread, url, std::move(callback)));
 }
 
@@ -458,8 +457,8 @@ void ArcDocumentsProviderAsyncFileUtil::DeleteRecursively(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_EQ(storage::kFileSystemTypeArcDocumentsProvider, url.type());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DeleteFileOnUIThread, url, std::move(callback)));
 }
 

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_file_stream_reader.cc

@@ -8,7 +8,6 @@
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_map.h"
@@ -29,8 +28,8 @@ void OnResolveToContentUrlOnUIThread(
     ArcDocumentsProviderRoot::ResolveToContentUrlCallback callback,
     const GURL& url) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), url));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), url));
 }
 
 void ResolveToContentUrlOnUIThread(
@@ -65,8 +64,8 @@ ArcDocumentsProviderFileStreamReader::ArcDocumentsProviderFileStreamReader(
     : offset_(offset), content_url_resolved_(false) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &ResolveToContentUrlOnUIThread, url,
           base::BindOnce(

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_file_stream_writer.cc

@@ -8,7 +8,6 @@
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_writer.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_map.h"
@@ -28,8 +27,8 @@ void OnResolveToContentUrlOnUIThread(
     ArcDocumentsProviderRoot::ResolveToContentUrlCallback callback,
     const GURL& url) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), url));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), url));
 }
 
 void ResolveToContentUrlOnUIThread(
@@ -83,8 +82,8 @@ int ArcDocumentsProviderFileStreamWriter::Write(
 
     // Resolve the |arc_url_| to a Content URL to instantiate the underlying
     // writer.
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(
             &ResolveToContentUrlOnUIThread, arc_url_,
             base::BindOnce(

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_watcher_manager.cc

@@ -7,7 +7,6 @@
 #include "base/bind.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_map.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -24,23 +23,23 @@ namespace {
 void OnAddWatcherOnUIThread(storage::WatcherManager::StatusCallback callback,
                             base::File::Error result) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 void OnRemoveWatcherOnUIThread(storage::WatcherManager::StatusCallback callback,
                                base::File::Error result) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 void OnNotificationOnUIThread(
     storage::WatcherManager::NotificationCallback notification_callback,
     ArcDocumentsProviderRoot::ChangeType change_type) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(notification_callback), change_type));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(notification_callback), change_type));
 }
 
 void AddWatcherOnUIThread(
@@ -118,8 +117,8 @@ void ArcDocumentsProviderWatcherManager::AddWatcher(
     return;
   }
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &AddWatcherOnUIThread, url,
           base::BindOnce(&ArcDocumentsProviderWatcherManager::OnAddWatcher,
@@ -142,8 +141,8 @@ void ArcDocumentsProviderWatcherManager::RemoveWatcher(
     return;
   }
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &RemoveWatcherOnUIThread, url,
           base::BindOnce(&ArcDocumentsProviderWatcherManager::OnRemoveWatcher,

chrome/browser/chromeos/arc/fileapi/arc_file_system_operation_runner_util.cc

@@ -8,7 +8,6 @@
 #include <vector>
 
 #include "base/bind.h"
-#include "base/task/post_task.h"
 #include "components/arc/arc_service_manager.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -32,8 +31,8 @@ ArcFileSystemOperationRunner* GetArcFileSystemOperationRunner() {
 template <typename T>
 void PostToIOThread(base::OnceCallback<void(T)> callback, T result) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), std::move(result)));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), std::move(result)));
 }
 
 void GetFileSizeOnUIThread(const GURL& url, GetFileSizeCallback callback) {
@@ -78,8 +77,8 @@ void OpenFileToWriteOnUIThread(const GURL& url,
 
 void GetFileSizeOnIOThread(const GURL& url, GetFileSizeCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&GetFileSizeOnUIThread, url,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&GetFileSizeOnUIThread, url,
                                 base::BindOnce(&PostToIOThread<int64_t>,
                                                std::move(callback))));
 }
@@ -87,8 +86,8 @@ void GetFileSizeOnIOThread(const GURL& url, GetFileSizeCallback callback) {
 void OpenFileToReadOnIOThread(const GURL& url,
                               OpenFileToReadCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OpenFileToReadOnUIThread, url,
                      base::BindOnce(&PostToIOThread<mojo::ScopedHandle>,
                                     std::move(callback))));
@@ -97,8 +96,8 @@ void OpenFileToReadOnIOThread(const GURL& url,
 void OpenFileToWriteOnIOThread(const GURL& url,
                                OpenFileToReadCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OpenFileToWriteOnUIThread, url,
                      base::BindOnce(&PostToIOThread<mojo::ScopedHandle>,
                                     std::move(callback))));

chrome/browser/chromeos/arc/fileapi/file_stream_forwarder.cc

@@ -45,15 +45,15 @@ FileStreamForwarder::FileStreamForwarder(
            base::MayBlock()})),
       buf_(base::MakeRefCounted<net::IOBufferWithSize>(kBufSize)) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&FileStreamForwarder::Start, base::Unretained(this)));
 }
 
 void FileStreamForwarder::Destroy() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&FileStreamForwarder::DestroyOnIOThread,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&FileStreamForwarder::DestroyOnIOThread,
                                 base::Unretained(this)));
 }
 
@@ -140,8 +140,8 @@ void FileStreamForwarder::OnWriteCompleted(bool result) {
 void FileStreamForwarder::NotifyCompleted(bool result) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(!callback_.is_null());
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback_), result));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback_), result));
 }
 
 }  // namespace arc

chrome/browser/chromeos/boot_times_recorder.cc

@@ -22,7 +22,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/system/sys_info.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
@@ -472,8 +471,8 @@ void BootTimesRecorder::AddMarker(std::vector<TimeMarker>* vector,
     // Add the marker on the UI thread.
     // Note that it's safe to use an unretained pointer to the vector because
     // BootTimesRecorder's lifetime exceeds that of the UI thread message loop.
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&BootTimesRecorder::AddMarker,
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&BootTimesRecorder::AddMarker,
                                   base::Unretained(vector), marker));
   }
 }

chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc

@@ -225,7 +225,7 @@ class SingleEntryPropertiesGetterForFileSystemProvider {
     DCHECK(!callback_.is_null());
 
     std::move(callback_).Run(std::move(properties_), result);
-    base::DeleteSoon(FROM_HERE, {BrowserThread::UI}, this);
+    content::GetUIThreadTaskRunner({})->DeleteSoon(FROM_HERE, this);
   }
 
   // Given parameters.
@@ -401,7 +401,7 @@ class SingleEntryPropertiesGetterForDriveFs {
 
     std::move(callback_).Run(std::move(properties_),
                              drive::FileErrorToBaseFileError(error));
-    base::DeleteSoon(FROM_HERE, {BrowserThread::UI}, this);
+    content::GetUIThreadTaskRunner({})->DeleteSoon(FROM_HERE, this);
   }
 
   // Given parameters.
@@ -490,7 +490,7 @@ class SingleEntryPropertiesGetterForDocumentsProvider {
     DCHECK(callback_);
 
     std::move(callback_).Run(std::move(properties_), error);
-    base::DeleteSoon(FROM_HERE, {BrowserThread::UI}, this);
+    content::GetUIThreadTaskRunner({})->DeleteSoon(FROM_HERE, this);
   }
 
   // Given parameters.

chrome/browser/chromeos/extensions/file_manager/private_api_file_system.cc

@@ -20,7 +20,6 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/system/sys_info.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/task_runner_util.h"
 #include "chrome/browser/browser_process.h"
@@ -161,8 +160,8 @@ void OnCopyProgress(
     int64_t size) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&NotifyCopyProgress, profile_id, *operation_id,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&NotifyCopyProgress, profile_id, *operation_id,
                                 type, source_url, destination_url, size));
 }
 
@@ -193,8 +192,8 @@ void OnCopyCompleted(
     base::File::Error error) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&NotifyCopyCompletion, profile_id, *operation_id,
                      source_url, destination_url, error));
 }
@@ -259,8 +258,8 @@ void ComputeChecksumRespondOnUIThread(
     base::OnceCallback<void(std::string)> callback,
     std::string hash) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), std::move(hash)));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), std::move(hash)));
 }
 
 // Calls a response callback on the UI thread.
@@ -269,8 +268,8 @@ void GetFileMetadataRespondOnUIThread(
     base::File::Error result,
     const base::File::Info& file_info) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), result, file_info));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result, file_info));
 }
 
 // Construct a case-insensitive fnmatch query from |query|. E.g.  for abc123,
@@ -411,16 +410,16 @@ void PostResponseCallbackTaskToUIThread(
     FileWatchFunctionBase::ResponseCallback callback,
     bool success) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), success));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), success));
 }
 
 void PostNotificationCallbackTaskToUIThread(
     storage::WatcherManager::NotificationCallback callback,
     storage::WatcherManager::ChangeType type) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), type));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), type));
 }
 
 }  // namespace
@@ -463,8 +462,8 @@ ExtensionFunction::ResponseAction FileWatchFunctionBase::Run() {
       file_manager::EventRouterFactory::GetForProfile(
           chrome_details.GetProfile());
 
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&FileWatchFunctionBase::RunAsyncOnIOThread,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&FileWatchFunctionBase::RunAsyncOnIOThread,
                                 this, file_system_context, file_system_url,
                                 event_router->GetWeakPtr()));
   return RespondLater();
@@ -480,8 +479,8 @@ void FileWatchFunctionBase::RunAsyncOnIOThread(
       file_system_context->GetWatcherManager(file_system_url.type());
 
   if (!watcher_manager) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(
             &FileWatchFunctionBase::PerformFallbackFileWatchOperationOnUIThread,
             this, file_system_url, event_router));
@@ -780,8 +779,8 @@ FileManagerPrivateInternalStartCopyFunction::Run() {
   }
 
   // Check how much space we need for the copy operation.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &GetFileMetadataOnIOThread, file_system_context, source_url_,
           storage::FileSystemOperation::GET_METADATA_FIELD_SIZE |
@@ -873,8 +872,8 @@ void FileManagerPrivateInternalStartCopyFunction::RunAfterFreeDiskSpace(
   scoped_refptr<storage::FileSystemContext> file_system_context =
       file_manager::util::GetFileSystemContextForRenderFrameHost(
           chrome_details_.GetProfile(), render_frame_host());
-  base::PostTaskAndReplyWithResult(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTaskAndReplyWithResult(
+      FROM_HERE,
       base::BindOnce(&StartCopyOnIOThread, chrome_details_.GetProfile(),
                      file_system_context, source_url_, destination_url_),
       base::BindOnce(
@@ -902,8 +901,8 @@ ExtensionFunction::ResponseAction FileManagerPrivateCancelCopyFunction::Run() {
           chrome_details.GetProfile(), render_frame_host());
 
   // We don't much take care about the result of cancellation.
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&CancelCopyOnIOThread, file_system_context,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&CancelCopyOnIOThread, file_system_context,
                                 params->copy_id));
   return RespondNow(NoArguments());
 }
@@ -1016,8 +1015,8 @@ FileManagerPrivateInternalComputeChecksumFunction::Run() {
       base::BindOnce(
           &FileManagerPrivateInternalComputeChecksumFunction::RespondWith,
           this));
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&FileStreamMd5Digester::GetMd5Digest,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&FileStreamMd5Digester::GetMd5Digest,
                                 base::Unretained(digester_.get()),
                                 std::move(reader), std::move(result_callback)));
 

chrome/browser/chromeos/extensions/wallpaper_private_api.cc

@@ -52,8 +52,6 @@
 #include "ui/strings/grit/app_locale_settings.h"
 
 using base::Value;
-using content::BrowserThread;
-
 namespace wallpaper_base = extensions::api::wallpaper;
 namespace wallpaper_private = extensions::api::wallpaper_private;
 namespace set_wallpaper_if_exists = wallpaper_private::SetWallpaperIfExists;
@@ -273,8 +271,8 @@ ExtensionFunction::ResponseAction WallpaperPrivateGetStringsFunction::Run() {
 
 ExtensionFunction::ResponseAction
 WallpaperPrivateGetSyncSettingFunction::Run() {
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &WallpaperPrivateGetSyncSettingFunction::CheckSyncServiceStatus,
           this));
@@ -337,8 +335,8 @@ void WallpaperPrivateGetSyncSettingFunction::CheckSyncServiceStatus() {
   // TODO(https://crbug.com/1036448): It would be cleaner to implement a
   // SyncServiceObserver and wait for OnStateChanged() instead of polling.
   retry_number_++;
-  base::PostDelayedTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE,
       base::BindOnce(
           &WallpaperPrivateGetSyncSettingFunction::CheckSyncServiceStatus,
           this),
@@ -591,19 +589,19 @@ void WallpaperPrivateGetThumbnailFunction::Get(const base::FilePath& path) {
   std::string data;
   if (GetData(path, &data)) {
     if (data.empty()) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&WallpaperPrivateGetThumbnailFunction::FileNotLoaded,
                          this));
     } else {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&WallpaperPrivateGetThumbnailFunction::FileLoaded,
                          this, data));
     }
   } else {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&WallpaperPrivateGetThumbnailFunction::Failure, this,
                        path.BaseName().value()));
   }
@@ -645,12 +643,12 @@ void WallpaperPrivateSaveThumbnailFunction::Save(
   WallpaperFunctionBase::AssertCalledOnWallpaperSequence(
       WallpaperFunctionBase::GetNonBlockingTaskRunner());
   if (SaveData(chrome::DIR_CHROMEOS_WALLPAPER_THUMBNAILS, file_name, data)) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&WallpaperPrivateSaveThumbnailFunction::Success, this));
   } else {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&WallpaperPrivateSaveThumbnailFunction::Failure, this,
                        file_name));
   }

chrome/browser/chromeos/external_metrics.cc

@@ -18,7 +18,6 @@
 #include "base/metrics/statistics_recorder.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/string_number_conversions.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "chrome/browser/metrics/chromeos_metrics_provider.h"
 #include "chromeos/constants/chromeos_switches.h"
@@ -27,8 +26,6 @@
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 
-using content::BrowserThread;
-
 namespace chromeos {
 
 namespace {
@@ -96,8 +93,8 @@ void ExternalMetrics::RecordActionUI(const std::string& action_string) {
 }
 
 void ExternalMetrics::RecordAction(const std::string& action) {
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ExternalMetrics::RecordActionUI, this, action));
 }
 
@@ -106,8 +103,8 @@ void ExternalMetrics::RecordCrashUI(const std::string& crash_kind) {
 }
 
 void ExternalMetrics::RecordCrash(const std::string& crash_kind) {
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ExternalMetrics::RecordCrashUI, this, crash_kind));
 }
 

chrome/browser/chromeos/file_manager/fileapi_util.cc

@@ -12,7 +12,6 @@
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/file_manager/app_id.h"
 #include "chrome/browser/chromeos/file_manager/filesystem_api_util.h"
 #include "chrome/browser/profiles/profile.h"
@@ -323,8 +322,8 @@ class ConvertSelectedFileInfoListToFileChooserFileInfoListImpl {
     // If the list includes at least one non-native file (wihtout a snapshot
     // file), move to IO thread to obtian metadata for the non-native file.
     if (need_fill_metadata) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(
               &ConvertSelectedFileInfoListToFileChooserFileInfoListImpl::
                   FillMetadataOnIOThread,
@@ -353,8 +352,8 @@ class ConvertSelectedFileInfoListToFileChooserFileInfoListImpl {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
     if (it == chooser_info_list_.end()) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(
               &ConvertSelectedFileInfoListToFileChooserFileInfoListImpl::
                   NotifyComplete,
@@ -386,8 +385,8 @@ class ConvertSelectedFileInfoListToFileChooserFileInfoListImpl {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
     if (result != base::File::FILE_OK) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(
               &ConvertSelectedFileInfoListToFileChooserFileInfoListImpl::
                   NotifyError,
@@ -567,8 +566,8 @@ void CheckIfDirectoryExists(
   const storage::FileSystemURL internal_url =
       backend->CreateInternalURL(file_system_context.get(), directory_path);
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CheckIfDirectoryExistsOnIoThread, file_system_context,
                      internal_url,
                      google_apis::CreateRelayCallback(std::move(callback))));
@@ -587,8 +586,8 @@ void GetMetadataForPath(
   const storage::FileSystemURL internal_url =
       backend->CreateInternalURL(file_system_context.get(), entry_path);
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&GetMetadataForPathOnIoThread, file_system_context,
                      internal_url, fields,
                      google_apis::CreateRelayCallback(std::move(callback))));

chrome/browser/chromeos/file_system_provider/fileapi/file_stream_reader.cc

@@ -11,7 +11,6 @@
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
-#include "base/task/post_task.h"
 #include "base/trace_event/trace_event.h"
 #include "chrome/browser/chromeos/file_system_provider/abort_callback.h"
 #include "chrome/browser/chromeos/file_system_provider/fileapi/provider_async_file_util.h"
@@ -50,8 +49,8 @@ class FileStreamReader::OperationRunner
 
     util::FileSystemURLParser parser(url);
     if (!parser.Parse()) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(std::move(callback), base::File::FILE_ERROR_SECURITY));
       return;
     }
@@ -78,8 +77,8 @@ class FileStreamReader::OperationRunner
 
     // If the file system got unmounted, then abort the reading operation.
     if (!file_system_.get()) {
-      base::PostTask(FROM_HERE, {BrowserThread::IO},
-                     base::BindOnce(callback, 0, false /* has_more */,
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(callback, 0, false /* has_more */,
                                     base::File::FILE_ERROR_ABORT));
       return;
     }
@@ -102,8 +101,8 @@ class FileStreamReader::OperationRunner
 
     // If the file system got unmounted, then abort the get length operation.
     if (!file_system_.get()) {
-      base::PostTask(FROM_HERE, {BrowserThread::IO},
-                     base::BindOnce(std::move(callback),
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(std::move(callback),
                                     base::WrapUnique<EntryMetadata>(NULL),
                                     base::File::FILE_ERROR_ABORT));
       return;
@@ -151,8 +150,8 @@ class FileStreamReader::OperationRunner
     if (result == base::File::FILE_OK)
       file_handle_ = file_handle;
 
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(std::move(callback), result));
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(std::move(callback), result));
   }
 
   // Forwards a metadata to the IO thread.
@@ -163,8 +162,8 @@ class FileStreamReader::OperationRunner
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
     abort_callback_ = AbortCallback();
 
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(std::move(callback), std::move(metadata), result));
   }
 
@@ -179,8 +178,8 @@ class FileStreamReader::OperationRunner
     if (!has_more)
       abort_callback_ = AbortCallback();
 
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(chunk_received_callback, chunk_length,
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(chunk_received_callback, chunk_length,
                                   has_more, result));
   }
 
@@ -208,8 +207,8 @@ FileStreamReader::~FileStreamReader() {
   // FileStreamReader doesn't have a Cancel() method like in FileStreamWriter.
   // Therefore, aborting and/or closing an opened file is done from the
   // destructor.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationRunner::CloseRunnerOnUIThread, runner_));
 
   // If a read is in progress, mark it as completed.
@@ -223,8 +222,8 @@ void FileStreamReader::Initialize(
   DCHECK_EQ(NOT_INITIALIZED, state_);
   state_ = INITIALIZING;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationRunner::OpenFileOnUIThread, runner_, url_,
                      base::BindOnce(&FileStreamReader::OnOpenFileCompleted,
                                     weak_ptr_factory_.GetWeakPtr(),
@@ -250,8 +249,8 @@ void FileStreamReader::OnOpenFileCompleted(
   DCHECK_EQ(base::File::FILE_OK, result);
 
   // Verify the last modification time.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationRunner::GetMetadataOnUIThread, runner_,
                      base::BindOnce(&FileStreamReader::OnInitializeCompleted,
                                     weak_ptr_factory_.GetWeakPtr(),
@@ -381,8 +380,8 @@ void FileStreamReader::ReadAfterInitialized(
   DCHECK_EQ(INITIALIZED, state_);
 
   current_length_ = 0;
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&OperationRunner::ReadFileOnUIThread, runner_,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&OperationRunner::ReadFileOnUIThread, runner_,
                                 buffer, current_offset_, buffer_length,
                                 base::BindRepeating(
                                     &FileStreamReader::OnReadChunkReceived,
@@ -393,8 +392,8 @@ void FileStreamReader::GetLengthAfterInitialized() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_EQ(INITIALIZED, state_);
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &OperationRunner::GetMetadataOnUIThread, runner_,
           base::BindOnce(&FileStreamReader::OnGetMetadataForGetLengthReceived,

chrome/browser/chromeos/file_system_provider/fileapi/file_stream_writer.cc

@@ -9,7 +9,6 @@
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "chrome/browser/chromeos/file_system_provider/abort_callback.h"
@@ -43,8 +42,8 @@ class FileStreamWriter::OperationRunner
 
     util::FileSystemURLParser parser(url);
     if (!parser.Parse()) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(std::move(callback), base::File::FILE_ERROR_SECURITY));
       return;
     }
@@ -67,8 +66,8 @@ class FileStreamWriter::OperationRunner
 
     // If the file system got unmounted, then abort the writing operation.
     if (!file_system_.get()) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(std::move(callback), base::File::FILE_ERROR_ABORT));
       return;
     }
@@ -113,8 +112,8 @@ class FileStreamWriter::OperationRunner
     if (result == base::File::FILE_OK)
       file_handle_ = file_handle;
 
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(std::move(callback), result));
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(std::move(callback), result));
   }
 
   // Forwards a response of writing to a file to the IO thread.
@@ -124,8 +123,8 @@ class FileStreamWriter::OperationRunner
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
     abort_callback_ = AbortCallback();
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(std::move(callback), result));
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(std::move(callback), result));
   }
 
   AbortCallback abort_callback_;
@@ -146,8 +145,8 @@ FileStreamWriter::FileStreamWriter(const storage::FileSystemURL& url,
 FileStreamWriter::~FileStreamWriter() {
   // Close the runner explicitly if the file streamer is
   if (state_ != CANCELLING) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&OperationRunner::CloseRunnerOnUIThread, runner_));
   }
 
@@ -162,8 +161,8 @@ void FileStreamWriter::Initialize(base::OnceClosure pending_closure,
   DCHECK_EQ(NOT_INITIALIZED, state_);
   state_ = INITIALIZING;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationRunner::OpenFileOnUIThread, runner_, url_,
                      base::BindOnce(&FileStreamWriter::OnOpenFileCompleted,
                                     weak_ptr_factory_.GetWeakPtr(),
@@ -248,8 +247,8 @@ int FileStreamWriter::Cancel(net::CompletionOnceCallback callback) {
   // Abort and optimistically return an OK result code, as the aborting
   // operation is always forced and can't be cancelled. Similarly, for closing
   // files.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationRunner::CloseRunnerOnUIThread, runner_));
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::BindOnce(std::move(callback), net::OK));
@@ -314,8 +313,8 @@ void FileStreamWriter::WriteAfterInitialized(
 
   state_ = EXECUTING;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationRunner::WriteFileOnUIThread, runner_, buffer,
                      current_offset_, buffer_length,
                      base::BindOnce(&FileStreamWriter::OnWriteFileCompleted,

chrome/browser/chromeos/file_system_provider/fileapi/provider_async_file_util.cc

@@ -15,7 +15,6 @@
 #include "base/memory/ptr_util.h"
 #include "base/notreached.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/file_system_provider/mount_path_util.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_interface.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -63,8 +62,8 @@ void OnGetFileInfo(int fields,
                    std::unique_ptr<EntryMetadata> metadata,
                    base::File::Error result) {
   if (result != base::File::FILE_OK) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(std::move(callback), result, base::File::Info()));
     return;
   }
@@ -87,8 +86,8 @@ void OnGetFileInfo(int fields,
 
   file_info.is_symbolic_link = false;  // Not supported.
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(std::move(callback), base::File::FILE_OK, file_info));
 }
 
@@ -130,8 +129,8 @@ void OnReadDirectory(storage::AsyncFileUtil::ReadDirectoryCallback callback,
                      });
   entry_list.erase(new_end_it, entry_list.end());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(callback, result, std::move(entry_list), has_more));
 }
 
@@ -163,8 +162,8 @@ void OnCreateDirectory(bool exclusive,
           ? base::File::FILE_OK
           : result;
 
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), error));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), error));
 }
 
 // Executes DeleteEntry on the UI thread.
@@ -186,8 +185,8 @@ void DeleteEntryOnUIThread(
 // Routes the response of DeleteEntry back to the IO thread.
 void OnDeleteEntry(storage::AsyncFileUtil::StatusCallback callback,
                    base::File::Error result) {
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 // Executes CreateFile on the UI thread.
@@ -216,8 +215,8 @@ void OnCreateFileForEnsureFileExists(
   const base::File::Error error =
       result == base::File::FILE_ERROR_EXISTS ? base::File::FILE_OK : result;
 
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), error, created));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), error, created));
 }
 
 // Executes CopyEntry on the UI thread.
@@ -244,8 +243,8 @@ void CopyEntryOnUIThread(
 // IO thread.
 void OnCopyEntry(storage::AsyncFileUtil::StatusCallback callback,
                  base::File::Error result) {
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 // Executes MoveEntry on the UI thread.
@@ -272,8 +271,8 @@ void MoveEntryOnUIThread(
 // IO thread.
 void OnMoveEntry(storage::AsyncFileUtil::StatusCallback callback,
                  base::File::Error result) {
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 // Executes Truncate on the UI thread.
@@ -295,8 +294,8 @@ void TruncateOnUIThread(
 // Routes the response of Truncate back to the IO thread.
 void OnTruncate(storage::AsyncFileUtil::StatusCallback callback,
                 base::File::Error result) {
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), result));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result));
 }
 
 }  // namespace
@@ -330,8 +329,8 @@ void ProviderAsyncFileUtil::EnsureFileExists(
     const storage::FileSystemURL& url,
     EnsureFileExistsCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&CreateFileOnUIThread, std::move(context), url,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&CreateFileOnUIThread, std::move(context), url,
                                 base::BindOnce(&OnCreateFileForEnsureFileExists,
                                                std::move(callback))));
 }
@@ -343,8 +342,8 @@ void ProviderAsyncFileUtil::CreateDirectory(
     bool recursive,
     StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&CreateDirectoryOnUIThread, std::move(context),
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&CreateDirectoryOnUIThread, std::move(context),
                                 url, exclusive, recursive,
                                 base::BindOnce(&OnCreateDirectory, exclusive,
                                                std::move(callback))));
@@ -356,8 +355,8 @@ void ProviderAsyncFileUtil::GetFileInfo(
     int fields,
     GetFileInfoCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &GetFileInfoOnUIThread, std::move(context), url, fields,
           base::Bind(&OnGetFileInfo, fields, base::Passed(&callback))));
@@ -368,8 +367,8 @@ void ProviderAsyncFileUtil::ReadDirectory(
     const storage::FileSystemURL& url,
     ReadDirectoryCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ReadDirectoryOnUIThread, std::move(context), url,
                      base::BindRepeating(&OnReadDirectory, callback)));
 }
@@ -390,8 +389,8 @@ void ProviderAsyncFileUtil::Truncate(
     int64_t length,
     StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&TruncateOnUIThread, std::move(context), url, length,
                      base::BindOnce(&OnTruncate, std::move(callback))));
 }
@@ -406,8 +405,8 @@ void ProviderAsyncFileUtil::CopyFileLocal(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   // TODO(mtomasz): Consier adding support for options (preserving last modified
   // time) as well as the progress callback.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CopyEntryOnUIThread, std::move(context), src_url,
                      dest_url,
                      base::BindOnce(&OnCopyEntry, std::move(callback))));
@@ -422,8 +421,8 @@ void ProviderAsyncFileUtil::MoveFileLocal(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   // TODO(mtomasz): Consier adding support for options (preserving last modified
   // time) as well as the progress callback.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&MoveEntryOnUIThread, std::move(context), src_url,
                      dest_url,
                      base::BindOnce(&OnMoveEntry, std::move(callback))));
@@ -443,8 +442,8 @@ void ProviderAsyncFileUtil::DeleteFile(
     const storage::FileSystemURL& url,
     StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DeleteEntryOnUIThread, std::move(context), url,
                      false,  // recursive
                      base::BindOnce(&OnDeleteEntry, std::move(callback))));
@@ -455,8 +454,8 @@ void ProviderAsyncFileUtil::DeleteDirectory(
     const storage::FileSystemURL& url,
     StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DeleteEntryOnUIThread, std::move(context), url,
                      false,  // recursive
                      base::BindOnce(&OnDeleteEntry, std::move(callback))));
@@ -467,8 +466,8 @@ void ProviderAsyncFileUtil::DeleteRecursively(
     const storage::FileSystemURL& url,
     StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DeleteEntryOnUIThread, std::move(context), url,
                      true,  // recursive
                      base::BindOnce(&OnDeleteEntry, std::move(callback))));

chrome/browser/chromeos/file_system_provider/fileapi/watcher_manager.cc

@@ -6,7 +6,6 @@
 
 #include "base/bind.h"
 #include "base/files/file.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/file_system_provider/mount_path_util.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_info.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_interface.h"
@@ -28,15 +27,15 @@ using ChangeType = storage::WatcherManager::ChangeType;
 void CallStatusCallbackOnIOThread(StatusCallback callback,
                                   base::File::Error error) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), error));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), error));
 }
 
 void CallNotificationCallbackOnIOThread(NotificationCallback callback,
                                         ChangeType type) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(std::move(callback), type));
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), type));
 }
 
 void AddWatcherOnUIThread(const storage::FileSystemURL& url,
@@ -92,8 +91,8 @@ void WatcherManager::AddWatcher(const storage::FileSystemURL& url,
                                 StatusCallback callback,
                                 NotificationCallback notification_callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &AddWatcherOnUIThread, url, recursive,
           base::BindOnce(&CallStatusCallbackOnIOThread, std::move(callback)),
@@ -105,8 +104,8 @@ void WatcherManager::RemoveWatcher(const storage::FileSystemURL& url,
                                    bool recursive,
                                    StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&RemoveWatcherOnUIThread, url, recursive,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&RemoveWatcherOnUIThread, url, recursive,
                                 base::BindOnce(&CallStatusCallbackOnIOThread,
                                                std::move(callback))));
 }

chrome/browser/chromeos/fileapi/recent_disk_source.cc

@@ -10,7 +10,6 @@
 #include "base/files/file_path.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/strings/string_util.h"
-#include "base/task/post_task.h"
 #include "base/time/time.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -39,8 +38,8 @@ void OnReadDirectoryOnIOThread(
     bool has_more) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(callback, result, std::move(entries), has_more));
 }
 
@@ -60,8 +59,8 @@ void OnGetMetadataOnIOThread(
     const base::File::Info& info) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(callback), result, info));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), result, info));
 }
 
 void GetMetadataOnIOThread(
@@ -153,8 +152,8 @@ void RecentDiskSource::ScanDirectory(const base::FilePath& path, int depth) {
   storage::FileSystemURL url = BuildDiskURL(path);
 
   ++inflight_readdirs_;
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &ReadDirectoryOnIOThread,
           base::WrapRefCounted(params_.value().file_system_context()), url,
@@ -191,8 +190,8 @@ void RecentDiskSource::OnReadDirectory(
       }
       storage::FileSystemURL url = BuildDiskURL(subpath);
       ++inflight_stats_;
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(
               &GetMetadataOnIOThread,
               base::WrapRefCounted(params_.value().file_system_context()), url,

chrome/browser/chromeos/login/lock/screen_locker.cc

@@ -23,7 +23,6 @@
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
@@ -79,8 +78,6 @@
 #include "url/gurl.h"
 
 using base::UserMetricsAction;
-using content::BrowserThread;
-
 namespace chromeos {
 
 namespace {
@@ -478,8 +475,8 @@ void ScreenLocker::ContinueAuthenticate(
                                         ->GetSupervisedUserManager()
                                         ->GetAuthentication()
                                         ->TransformKey(user_context);
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(
               &ExtendedAuthenticator::AuthenticateToCheck,
               extended_authenticator_.get(), updated_context,
@@ -502,8 +499,8 @@ void ScreenLocker::ContinueAuthenticate(
         user_context.GetKey()->GetSecret());
   }
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ExtendedAuthenticator::AuthenticateToCheck,
                      extended_authenticator_.get(), user_context,
                      base::Bind(&ScreenLocker::OnPasswordAuthSuccess,

chrome/browser/chromeos/login/signin/oauth2_token_fetcher.cc

@@ -7,7 +7,6 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
-#include "base/task/post_task.h"
 #include "chromeos/network/network_handler.h"
 #include "chromeos/network/network_state.h"
 #include "chromeos/network/network_state_handler.h"
@@ -76,8 +75,8 @@ void OAuth2TokenFetcher::RetryOnError(const GoogleServiceAuthError& error,
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (error.IsTransientError() && retry_count_ < kMaxRequestAttemptCount) {
     retry_count_++;
-    base::PostDelayedTask(
-        FROM_HERE, {BrowserThread::UI}, task,
+    content::GetUIThreadTaskRunner({})->PostDelayedTask(
+        FROM_HERE, task,
         base::TimeDelta::FromMilliseconds(kRequestRestartDelay));
     return;
   }

chrome/browser/chromeos/login/wizard_controller.cc

@@ -28,7 +28,6 @@
 #include "base/no_destructor.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/branding_buildflags.h"
@@ -1243,8 +1242,8 @@ void WizardController::OnOobeFlowFinished() {
   SetCurrentScreen(nullptr);
 
   // Launch browser and delete login host controller.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&UserSessionManager::DoBrowserLaunch,
                      base::Unretained(UserSessionManager::GetInstance()),
                      ProfileManager::GetActiveUserProfile(),

chrome/browser/chromeos/mobile/mobile_activator.cc

@@ -19,7 +19,6 @@
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/threading/scoped_blocking_call.h"
 #include "base/timer/timer.h"
 #include "base/values.h"
@@ -187,8 +186,8 @@ void MobileActivator::GetPropertiesFailure(
 }
 
 void MobileActivator::OnSetTransactionStatus(bool success) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&MobileActivator::HandleSetTransactionStatus,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&MobileActivator::HandleSetTransactionStatus,
                                 weak_ptr_factory_.GetWeakPtr(), success));
 }
 
@@ -212,8 +211,8 @@ void MobileActivator::HandleSetTransactionStatus(bool success) {
 }
 
 void MobileActivator::OnPortalLoaded(bool success) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&MobileActivator::HandlePortalLoaded,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&MobileActivator::HandlePortalLoaded,
                                 weak_ptr_factory_.GetWeakPtr(), success));
 }
 
@@ -845,8 +844,8 @@ void MobileActivator::ChangeState(const NetworkState* network,
       break;
     case PLAN_ACTIVATION_DELAY_OTASP: {
       UMA_HISTOGRAM_COUNTS_1M("Cellular.RetryOTASP", 1);
-      base::PostDelayedTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostDelayedTask(
+          FROM_HERE,
           base::BindOnce(&MobileActivator::RetryOTASP,
                          weak_ptr_factory_.GetWeakPtr()),
           base::TimeDelta::FromMilliseconds(kOTASPRetryDelay));

chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc

@@ -81,8 +81,8 @@ void LoadPrivateKeyByPublicKeyOnWorkerThread(
   scoped_refptr<PublicKey> public_key;
   if (!owner_key_util->ImportPublicKey(&public_key_data)) {
     scoped_refptr<PrivateKey> private_key;
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(callback, public_key, private_key));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(callback, public_key, private_key));
     return;
   }
   public_key = new PublicKey();
@@ -103,8 +103,8 @@ void LoadPrivateKeyByPublicKeyOnWorkerThread(
     private_key = new PrivateKey(owner_key_util->FindPrivateKeyInSlot(
         public_key->data(), public_slot.get()));
   }
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(callback, public_key, private_key));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(callback, public_key, private_key));
 }
 
 void ContinueLoadPrivateKeyOnIOThread(
@@ -389,8 +389,8 @@ void OwnerSettingsServiceChromeOS::IsOwnerForSafeModeAsync(
 
   // Make sure NSS is initialized and NSS DB is loaded for the user before
   // searching for the owner key.
-  base::PostTaskAndReply(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTaskAndReply(
+      FROM_HERE,
       base::BindOnce(base::IgnoreResult(&crypto::InitializeNSSForChromeOSUser),
                      user_hash,
                      ProfileHelper::GetProfilePathByUserIdHash(user_hash)),
@@ -701,8 +701,8 @@ void OwnerSettingsServiceChromeOS::ReloadKeypairImpl(const base::Callback<
   if (waiting_for_tpm_token_ || waiting_for_easy_unlock_operation_finshed_)
     return;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&LoadPrivateKeyOnIOThread, owner_key_util_,
                      ProfileHelper::GetUserIdHashFromProfile(profile_),
                      callback));

chrome/browser/chromeos/platform_keys/platform_keys_service_nss.cc

@@ -25,7 +25,6 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/single_thread_task_runner.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/browser_process.h"
@@ -170,8 +169,8 @@ void DidGetSystemTokenCertDbOnUiThread(const std::string& token_id,
 
   // Sets |slot_| of |state| accordingly and calls |callback| on the IO thread
   // if the database was successfully retrieved.
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&DidGetCertDbOnIoThread, token_id, callback,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&DidGetCertDbOnIoThread, token_id, callback,
                                 state, cert_db));
 }
 
@@ -196,8 +195,8 @@ void GetCertDatabase(const std::string& token_id,
     return;
   }
 
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&GetCertDatabaseOnIoThread, token_id, callback,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&GetCertDatabaseOnIoThread, token_id, callback,
                                 browser_context->GetResourceContext(), state));
 }
 
@@ -988,8 +987,8 @@ void DidSelectCertificates(std::unique_ptr<SelectCertificatesState> state,
     certs->push_back(identity->certificate());
   // DidSelectCertificates() may be called synchronously, so run the callback on
   // a separate event loop iteration to avoid potential reentrancy bugs.
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&SelectCertificatesState::CallBack,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&SelectCertificatesState::CallBack,
                                 std::move(state), FROM_HERE, std::move(certs),
                                 std::string() /* no error */));
 }

chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.cc

@@ -12,7 +12,6 @@
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string_util.h"
-#include "base/task/post_task.h"
 #include "chromeos/constants/chromeos_switches.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -219,8 +218,8 @@ void PolicyOAuth2TokenFetcherImpl::RetryOnError(
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (error.IsTransientError() && retry_count_ < kMaxRequestAttemptCount) {
     retry_count_++;
-    base::PostDelayedTask(
-        FROM_HERE, {BrowserThread::UI}, task,
+    content::GetUIThreadTaskRunner({})->PostDelayedTask(
+        FROM_HERE, task,
         base::TimeDelta::FromMilliseconds(kRequestRestartDelay));
     return;
   }

chrome/browser/chromeos/proxy_config_service_impl_unittest.cc

@@ -15,7 +15,6 @@
 #include "base/run_loop.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chromeos/settings/scoped_cros_settings_test_helper.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/shill/shill_profile_client.h"
@@ -31,6 +30,7 @@
 #include "components/proxy_config/proxy_config_pref_names.h"
 #include "components/sync_preferences/testing_pref_service_syncable.h"
 #include "content/public/browser/browser_task_traits.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/test/browser_task_environment.h"
 #include "net/proxy_resolution/proxy_config.h"
 #include "net/proxy_resolution/proxy_config_service_common_unittest.h"
@@ -42,8 +42,6 @@
 // rename. This is really more of an integration test than a unit test at this
 // point and currently relies on some chrome specific components.
 
-using content::BrowserThread;
-
 namespace chromeos {
 
 namespace {
@@ -274,8 +272,7 @@ class ProxyConfigServiceImplTest : public testing::Test {
 
   void SetUpProxyConfigService(PrefService* profile_prefs) {
     config_service_impl_.reset(new ProxyConfigServiceImpl(
-        profile_prefs, &pref_service_,
-        base::CreateSingleThreadTaskRunner({BrowserThread::IO})));
+        profile_prefs, &pref_service_, content::GetIOThreadTaskRunner({})));
     proxy_config_service_ =
         config_service_impl_->CreateTrackingProxyConfigService(
             std::unique_ptr<net::ProxyConfigService>());

chrome/browser/component_updater/games_component_installer.cc

@@ -11,7 +11,6 @@
 #include "base/feature_list.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
-#include "base/task/post_task.h"
 #include "base/task/task_traits.h"
 #include "base/time/time.h"
 #include "build/branding_buildflags.h"
@@ -56,8 +55,8 @@ void RegisterGamesComponentHelper(ComponentUpdateService* cus,
     VLOG(1) << "Registering Games component.";
 
     auto lambda = [](PrefService* prefs, const base::FilePath& install_dir) {
-      base::PostTask(FROM_HERE,
-                     {BrowserThread::UI, base::TaskPriority::BEST_EFFORT},
+      content::GetUIThreadTaskRunner({base::TaskPriority::BEST_EFFORT})
+          ->PostTask(FROM_HERE,
                      base::BindOnce(&UpdateInstallDirPref, prefs, install_dir));
     };
 
@@ -137,8 +136,8 @@ std::vector<std::string> GamesComponentInstallerPolicy::GetMimeTypes() const {
 void RegisterGamesComponent(ComponentUpdateService* cus, PrefService* prefs) {
   // We delay the registration because we are not required in the critical path
   // during browser setup.
-  base::PostTask(FROM_HERE,
-                 {BrowserThread::UI, base::TaskPriority::BEST_EFFORT},
+  content::GetUIThreadTaskRunner({base::TaskPriority::BEST_EFFORT})
+      ->PostTask(FROM_HERE,
                  base::BindOnce(&RegisterGamesComponentHelper, cus, prefs));
 }
 

chrome/browser/component_updater/recovery_component_installer.cc

@@ -351,8 +351,8 @@ void WaitForInstallToComplete(base::Process process,
     if (installer_exit_code == EXIT_CODE_ELEVATION_NEEDED) {
       RecordRecoveryComponentUMAEvent(RCE_ELEVATION_NEEDED);
 
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(&SetPrefsForElevatedRecoveryInstall,
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&SetPrefsForElevatedRecoveryInstall,
                                     installer_folder, prefs));
     } else if (installer_exit_code == EXIT_CODE_RECOVERY_SUCCEEDED) {
       RecordRecoveryComponentUMAEvent(RCE_SUCCEEDED);
@@ -476,8 +476,8 @@ bool RecoveryComponentInstaller::DoInstall(
 
   current_version_ = version;
   if (prefs_) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&RecoveryUpdateVersionHelper, version, prefs_));
   }
   return true;
@@ -501,15 +501,15 @@ void RegisterRecoveryComponent(ComponentUpdateService* cus,
 #if BUILDFLAG(GOOGLE_CHROME_BRANDING)
 #if defined(OS_WIN) || defined(OS_MACOSX)
   if (SimulatingElevatedRecovery()) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&SimulateElevatedRecoveryHelper, prefs));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&SimulateElevatedRecoveryHelper, prefs));
   }
 
   // We delay execute the registration because we are not required in
   // the critical path during browser startup.
-  base::PostDelayedTask(FROM_HERE, {BrowserThread::UI},
-                        base::BindOnce(&RecoveryRegisterHelper, cus, prefs),
-                        base::TimeDelta::FromSeconds(6));
+  content::GetUIThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE, base::BindOnce(&RecoveryRegisterHelper, cus, prefs),
+      base::TimeDelta::FromSeconds(6));
 #endif
 #endif
 }

chrome/browser/component_updater/soda_component_installer.cc

@@ -6,7 +6,6 @@
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/common/pref_names.h"
@@ -15,6 +14,7 @@
 #include "components/soda/constants.h"
 #include "components/update_client/update_client_errors.h"
 #include "content/public/browser/browser_task_traits.h"
+#include "content/public/browser/browser_thread.h"
 #include "crypto/sha2.h"
 
 using content::BrowserThread;
@@ -134,9 +134,9 @@ void RegisterSODAComponent(ComponentUpdateService* cus,
   auto installer = base::MakeRefCounted<ComponentInstaller>(
       std::make_unique<SODAComponentInstallerPolicy>(base::BindRepeating(
           [](PrefService* prefs, const base::FilePath& install_dir) {
-            base::PostTask(
-                FROM_HERE, {BrowserThread::UI, base::TaskPriority::BEST_EFFORT},
-                base::BindOnce(&UpdateSODAInstallDirPref, prefs, install_dir));
+            content::GetUIThreadTaskRunner({base::TaskPriority::BEST_EFFORT})
+                ->PostTask(FROM_HERE, base::BindOnce(&UpdateSODAInstallDirPref,
+                                                     prefs, install_dir));
           },
           prefs)));
   installer->Register(cus, std::move(callback));

chrome/browser/devtools/device/adb/mock_adb_server.cc

@@ -18,7 +18,6 @@
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
@@ -651,17 +650,16 @@ void MockAndroidConnection::SendHTTPResponse(const std::string& body) {
 
 void StartMockAdbServer(FlushMode flush_mode) {
   base::RunLoop run_loop;
-  base::PostTaskAndReply(
-      FROM_HERE, {BrowserThread::IO},
-      base::BindOnce(&StartMockAdbServerOnIOThread, flush_mode),
+  content::GetIOThreadTaskRunner({})->PostTaskAndReply(
+      FROM_HERE, base::BindOnce(&StartMockAdbServerOnIOThread, flush_mode),
       run_loop.QuitClosure());
   run_loop.Run();
 }
 
 void StopMockAdbServer() {
   base::RunLoop run_loop;
-  base::PostTaskAndReply(FROM_HERE, {BrowserThread::IO},
-                         base::BindOnce(&StopMockAdbServerOnIOThread),
-                         run_loop.QuitClosure());
+  content::GetIOThreadTaskRunner({})->PostTaskAndReply(
+      FROM_HERE, base::BindOnce(&StopMockAdbServerOnIOThread),
+      run_loop.QuitClosure());
   run_loop.Run();
 }

chrome/browser/devtools/device/android_device_manager.cc

@@ -17,7 +17,6 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ -382,8 +381,8 @@ class DevicesRequest : public base::RefCountedThreadSafe<DevicesRequest> {
 
 void OnCountDevices(const base::Callback<void(int)>& callback,
                     int device_count) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(callback, device_count));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(callback, device_count));
 }
 
 }  // namespace

chrome/browser/devtools/device/devtools_device_discovery.cc

@@ -16,7 +16,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/values.h"
 #include "chrome/browser/devtools/devtools_window.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -46,8 +45,8 @@ const char kPageReloadCommand[] = "{'method': 'Page.reload', id: 1}";
 const char kWebViewSocketPrefix[] = "webview_devtools_remote";
 
 static void ScheduleTaskDefault(const base::Closure& task) {
-  base::PostDelayedTask(FROM_HERE, {BrowserThread::UI}, task,
-                        base::TimeDelta::FromMilliseconds(kPollingIntervalMs));
+  content::GetUIThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE, task, base::TimeDelta::FromMilliseconds(kPollingIntervalMs));
 }
 
 // ProtocolCommand ------------------------------------------------------------

chrome/browser/devtools/device/usb/android_usb_browsertest.cc

@@ -17,7 +17,6 @@
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/devtools/device/adb/mock_adb_server.h"
 #include "chrome/browser/devtools/device/devtools_android_bridge.h"
@@ -527,7 +526,7 @@ class AndroidUsbDiscoveryTest : public InProcessBrowserTest {
   void ScheduleDeviceCountRequest(const base::Closure& request) {
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
     scheduler_invoked_++;
-    base::PostTask(FROM_HERE, {BrowserThread::UI}, request);
+    content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE, request);
   }
 
   virtual std::unique_ptr<FakeUsbDeviceManager> CreateFakeUsbManager() {

chrome/browser/devtools/devtools_file_system_indexer.cc

@@ -20,7 +20,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task/lazy_thread_pool_task_runner.h"
-#include "base/task/post_task.h"
 #include "content/public/browser/browser_task_traits.h"
 
 #include "content/public/browser/browser_thread.h"
@@ -322,8 +321,8 @@ void DevToolsFileSystemIndexer::FileSystemIndexingJob::CollectFilesToIndex() {
   }
 
   if (file_path.empty()) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   BindOnce(total_work_callback_, file_path_times_.size()));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, BindOnce(total_work_callback_, file_path_times_.size()));
     indexing_it_ = file_path_times_.begin();
     IndexFiles();
     return;
@@ -359,7 +358,7 @@ void DevToolsFileSystemIndexer::FileSystemIndexingJob::IndexFiles() {
     return;
   if (indexing_it_ == file_path_times_.end()) {
     g_trigram_index.Get().NormalizeVectors();
-    base::PostTask(FROM_HERE, {BrowserThread::UI}, done_callback_);
+    content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE, done_callback_);
     return;
   }
   FilePath file_path = indexing_it_->first;
@@ -451,8 +450,8 @@ void DevToolsFileSystemIndexer::FileSystemIndexingJob::ReportWorked() {
   ++files_indexed_;
   if (should_send_worked_nitification) {
     last_worked_notification_time_ = current_time;
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   BindOnce(worked_callback_, files_indexed_));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, BindOnce(worked_callback_, files_indexed_));
     files_indexed_ = 0;
   }
 }
@@ -515,6 +514,6 @@ void DevToolsFileSystemIndexer::SearchInPathOnImplSequence(
     if (path.IsParent(*it))
       result.push_back(it->AsUTF8Unsafe());
   }
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 BindOnce(callback, std::move(result)));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, BindOnce(callback, std::move(result)));
 }

chrome/browser/devtools/devtools_sanity_browsertest.cc

@@ -24,7 +24,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/test/scoped_feature_list.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/thread_restrictions.h"
@@ -114,7 +113,6 @@
 #include "chromeos/constants/chromeos_switches.h"
 #endif
 
-using content::BrowserThread;
 using content::DevToolsAgentHost;
 using content::DevToolsAgentHostObserver;
 using content::NavigationController;
@@ -632,7 +630,7 @@ class WorkerDevToolsSanityTest : public InProcessBrowserTest {
       if (host->GetType() == DevToolsAgentHost::kTypeSharedWorker &&
           host->GetURL().path().rfind(path_) != std::string::npos) {
         *out_host_ = host;
-        base::PostTask(FROM_HERE, {BrowserThread::UI}, quit_);
+        content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE, quit_);
         delete this;
       }
     }

chrome/browser/download/android/download_controller.cc

@@ -18,7 +18,6 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/notreached.h"
 #include "base/synchronization/lock.h"
-#include "base/task/post_task.h"
 #include "chrome/android/chrome_jni_headers/DownloadController_jni.h"
 #include "chrome/browser/android/profile_key_util.h"
 #include "chrome/browser/android/tab_android.h"
@@ -264,14 +263,14 @@ void DownloadController::AcquireFileAccessPermission(
         StoragePermissionType::STORAGE_PERMISSION_REQUESTED);
     RecordStoragePermission(
         StoragePermissionType::STORAGE_PERMISSION_NO_ACTION_NEEDED);
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(std::move(cb), true));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(std::move(cb), true));
     return;
   } else if (vr::VrTabHelper::IsUiSuppressedInVr(
                  web_contents,
                  vr::UiSuppressedElement::kFileAccessPermission)) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(std::move(cb), false));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(std::move(cb), false));
     return;
   }
 
@@ -289,8 +288,8 @@ void DownloadController::AcquireFileAccessPermission(
 void DownloadController::CreateAndroidDownload(
     const content::WebContents::Getter& wc_getter,
     const DownloadInfo& info) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&DownloadController::StartAndroidDownload,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&DownloadController::StartAndroidDownload,
                                 base::Unretained(this), wc_getter, info));
 }
 
@@ -451,8 +450,8 @@ void DownloadController::OnDangerousDownload(DownloadItem* item) {
     auto download_manager_getter = std::make_unique<DownloadManagerGetter>(
         BrowserContext::GetDownloadManager(
             content::DownloadItemUtils::GetBrowserContext(item)));
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&RemoveDownloadItem, std::move(download_manager_getter),
                        item->GetGuid()));
     item->RemoveObserver(this);
@@ -469,8 +468,8 @@ void DownloadController::OnMixedContentDownload(DownloadItem* item) {
     auto download_manager_getter = std::make_unique<DownloadManagerGetter>(
         BrowserContext::GetDownloadManager(
             content::DownloadItemUtils::GetBrowserContext(item)));
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&RemoveDownloadItem, std::move(download_manager_getter),
                        item->GetGuid()));
     item->RemoveObserver(this);

chrome/browser/download/download_request_limiter.cc

@@ -9,7 +9,6 @@
 
 #include "base/bind.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "chrome/browser/content_settings/chrome_content_settings_utils.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
@@ -401,8 +400,8 @@ bool DownloadRequestLimiter::TabDownloadState::NotifyCallbacks(bool allow) {
 
   for (auto& callback : callbacks) {
     // When callback runs, it can cause the WebContents to be destroyed.
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(std::move(callback), allow));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(std::move(callback), allow));
   }
 
   return throttled;

chrome/browser/download/download_target_determiner.cc

@@ -676,8 +676,8 @@ void IsHandledBySafePlugin(int render_process_id,
       (plugin_info.type == WebPluginInfo::PLUGIN_TYPE_PEPPER_IN_PROCESS ||
        plugin_info.type == WebPluginInfo::PLUGIN_TYPE_PEPPER_OUT_OF_PROCESS ||
        plugin_info.type == WebPluginInfo::PLUGIN_TYPE_BROWSER_PLUGIN);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(callback, is_handled_safely));
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(callback, is_handled_safely));
 }
 
 }  // namespace

chrome/browser/engagement/important_sites_usage_counter_unittest.cc

@@ -12,7 +12,6 @@
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/run_loop.h"
-#include "base/task/post_task.h"
 #include "base/test/metrics/histogram_tester.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "chrome/test/base/testing_profile.h"
@@ -26,7 +25,6 @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 using ImportantDomainInfo = ImportantSitesUtil::ImportantDomainInfo;
-using content::BrowserThread;
 using content::DOMStorageContext;
 using storage::QuotaManager;
 
@@ -46,10 +44,9 @@ class ImportantSitesUsageCounterTest : public testing::Test {
   TestingProfile* profile() { return &profile_; }
 
   QuotaManager* CreateQuotaManager() {
-    quota_manager_ = new QuotaManager(
-        false, temp_dir_.GetPath(),
-        base::CreateSingleThreadTaskRunner({BrowserThread::IO}).get(), nullptr,
-        storage::GetQuotaSettingsFunc());
+    quota_manager_ = new QuotaManager(false, temp_dir_.GetPath(),
+                                      content::GetIOThreadTaskRunner({}).get(),
+                                      nullptr, storage::GetQuotaSettingsFunc());
     return quota_manager_.get();
   }
 

chrome/browser/extensions/api/braille_display_private/braille_controller_brlapi.cc

@@ -15,7 +15,6 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/scoped_blocking_call.h"
 #include "base/time/time.h"
@@ -137,9 +136,9 @@ void BrailleControllerImpl::WriteDots(const std::vector<uint8_t>& cells,
 
 void BrailleControllerImpl::AddObserver(BrailleObserver* observer) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (!base::PostTask(FROM_HERE, {BrowserThread::IO},
-                      base::BindOnce(&BrailleControllerImpl::StartConnecting,
-                                     base::Unretained(this)))) {
+  if (!content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&BrailleControllerImpl::StartConnecting,
+                                    base::Unretained(this)))) {
     NOTREACHED();
   }
   observers_.AddObserver(observer);
@@ -215,8 +214,8 @@ void BrailleControllerImpl::OnSocketDirChangedOnTaskThread(
     LOG(ERROR) << "Error watching brlapi directory: " << path.value();
     return;
   }
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&BrailleControllerImpl::OnSocketDirChangedOnIOThread,
                      base::Unretained(this)));
 }
@@ -274,10 +273,11 @@ void BrailleControllerImpl::ScheduleTryToConnect() {
   }
   VLOG(1) << "Scheduling connection retry to brlapi";
   connect_scheduled_ = true;
-  base::PostDelayedTask(FROM_HERE, {BrowserThread::IO},
-                        base::BindOnce(&BrailleControllerImpl::TryToConnect,
-                                       base::Unretained(this)),
-                        kConnectionDelay);
+  content::GetIOThreadTaskRunner({})->PostDelayedTask(
+      FROM_HERE,
+      base::BindOnce(&BrailleControllerImpl::TryToConnect,
+                     base::Unretained(this)),
+      kConnectionDelay);
 }
 
 void BrailleControllerImpl::Disconnect() {
@@ -319,8 +319,8 @@ void BrailleControllerImpl::DispatchKeys() {
 
 void BrailleControllerImpl::DispatchKeyEvent(std::unique_ptr<KeyEvent> event) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&BrailleControllerImpl::DispatchKeyEvent,
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&BrailleControllerImpl::DispatchKeyEvent,
                                   base::Unretained(this), std::move(event)));
     return;
   }
@@ -332,8 +332,8 @@ void BrailleControllerImpl::DispatchKeyEvent(std::unique_ptr<KeyEvent> event) {
 void BrailleControllerImpl::DispatchOnDisplayStateChanged(
     std::unique_ptr<DisplayState> new_state) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    if (!base::PostTask(
-            FROM_HERE, {BrowserThread::UI},
+    if (!content::GetUIThreadTaskRunner({})->PostTask(
+            FROM_HERE,
             base::BindOnce(
                 &BrailleControllerImpl::DispatchOnDisplayStateChanged,
                 base::Unretained(this), std::move(new_state)))) {

chrome/browser/extensions/api/browsing_data/browsing_data_api.cc

@@ -12,7 +12,6 @@
 #include <utility>
 
 #include "base/bind.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/values.h"
 #include "chrome/browser/browsing_data/chrome_browsing_data_remover_delegate.h"
@@ -391,8 +390,8 @@ void BrowsingDataRemoverFunction::CheckRemovingPluginDataSupported(
   if (!PluginDataRemoverHelper::IsSupported(plugin_prefs.get()))
     removal_mask_ &= ~ChromeBrowsingDataRemoverDelegate::DATA_TYPE_PLUGIN_DATA;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&BrowsingDataRemoverFunction::StartRemoving, this));
 }
 #endif

chrome/browser/extensions/api/downloads/downloads_api_browsertest.cc

@@ -18,7 +18,6 @@
 #include "base/run_loop.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "base/test/bind_test_util.h"
 #include "base/test/scoped_feature_list.h"
 #include "base/threading/thread_restrictions.h"
@@ -114,8 +113,8 @@ void OnOpenPromptCreated(download::DownloadItem* item,
                          DownloadOpenPrompt* prompt) {
   EXPECT_FALSE(item->GetOpened());
   // Posts a task to accept the DownloadOpenPrompt.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&DownloadOpenPrompt::AcceptConfirmationDialogForTesting,
                      base::Unretained(prompt)));
 }
@@ -709,8 +708,8 @@ class MockIconExtractorImpl : public DownloadFileIconExtractor {
     if (expected_path_ == path &&
         expected_icon_size_ == icon_size) {
       callback_ = callback;
-      base::PostTask(FROM_HERE, {BrowserThread::UI},
-                     base::BindOnce(&MockIconExtractorImpl::RunCallback,
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&MockIconExtractorImpl::RunCallback,
                                     base::Unretained(this)));
       return true;
     } else {
@@ -793,8 +792,8 @@ class HTML5FileWriter {
     // Invoke the fileapi to copy it into the sandboxed filesystem.
     bool result = false;
     base::RunLoop run_loop;
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&CreateFileForTestingOnIOThread,
                        base::Unretained(context), path, temp_file,
                        base::Unretained(&result), run_loop.QuitClosure()));
@@ -810,7 +809,7 @@ class HTML5FileWriter {
                                base::File::Error error) {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
     *result = error == base::File::FILE_OK;
-    base::PostTask(FROM_HERE, {BrowserThread::UI}, quit_closure);
+    content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE, quit_closure);
   }
 
   static void CreateFileForTestingOnIOThread(

chrome/browser/extensions/api/image_writer_private/operation.cc

@@ -8,7 +8,6 @@
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/image_writer_private/error_messages.h"
@@ -20,8 +19,6 @@
 namespace extensions {
 namespace image_writer {
 
-using content::BrowserThread;
-
 namespace {
 
 const int kMD5BufferSize = 1024;
@@ -129,16 +126,16 @@ void Operation::Finish() {
 
   CleanUp();
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationManager::OnComplete, manager_, extension_id_));
 }
 
 void Operation::Error(const std::string& error_message) {
   DCHECK(IsRunningInCorrectSequence());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&OperationManager::OnError, manager_, extension_id_,
                      stage_, progress_, error_message));
 
@@ -158,8 +155,8 @@ void Operation::SetProgress(int progress) {
 
   progress_ = progress;
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&OperationManager::OnProgress, manager_,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&OperationManager::OnProgress, manager_,
                                 extension_id_, stage_, progress_));
 }
 
@@ -172,8 +169,8 @@ void Operation::SetStage(image_writer_api::Stage stage) {
   stage_ = stage;
   progress_ = 0;
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&OperationManager::OnProgress, manager_,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&OperationManager::OnProgress, manager_,
                                 extension_id_, stage_, progress_));
 }
 

chrome/browser/extensions/api/image_writer_private/operation_chromeos.cc

@@ -5,7 +5,6 @@
 #include <stdint.h>
 
 #include "base/bind.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/extensions/api/image_writer_private/error_messages.h"
 #include "chrome/browser/extensions/api/image_writer_private/operation.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
@@ -26,8 +25,8 @@ namespace {
 
 void ClearImageBurner() {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&ClearImageBurner));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&ClearImageBurner));
     return;
   }
 
@@ -45,8 +44,8 @@ void Operation::Write(const base::Closure& continuation) {
   // Note this has to be run on the FILE thread to avoid concurrent access.
   AddCleanUpFunction(base::BindOnce(&ClearImageBurner));
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&Operation::UnmountVolumes, this, continuation));
 }
 

chrome/browser/extensions/api/messaging/native_message_process_host_unittest.cc

@@ -27,7 +27,6 @@
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/test/scoped_feature_list.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/platform_thread.h"
@@ -59,8 +58,6 @@
 #include <unistd.h>
 #endif
 
-using content::BrowserThread;
-
 namespace {
 
 const char kTestMessage[] = "{\"text\": \"Hello.\"}";
@@ -125,8 +122,8 @@ class NativeMessagingTest : public ::testing::Test,
 
   void TearDown() override {
     if (native_message_host_) {
-      base::DeleteSoon(FROM_HERE, {BrowserThread::IO},
-                       native_message_host_.release());
+      content::GetIOThreadTaskRunner({})->DeleteSoon(
+          FROM_HERE, native_message_host_.release());
     }
     base::RunLoop().RunUntilIdle();
   }

chrome/browser/extensions/api/page_capture/page_capture_api.cc

@@ -11,7 +11,6 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_util.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
@@ -76,8 +75,8 @@ PageCaptureSaveAsMHTMLFunction::PageCaptureSaveAsMHTMLFunction() {
 
 PageCaptureSaveAsMHTMLFunction::~PageCaptureSaveAsMHTMLFunction() {
   if (mhtml_file_.get()) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&ClearFileReferenceOnIOThread, std::move(mhtml_file_)));
   }
 }
@@ -200,8 +199,8 @@ void PageCaptureSaveAsMHTMLFunction::ResolvePermissionRequest(
 
 void PageCaptureSaveAsMHTMLFunction::CreateTemporaryFile() {
   bool success = base::CreateTemporaryFile(&mhtml_path_);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&PageCaptureSaveAsMHTMLFunction::TemporaryFileCreatedOnIO,
                      this, success));
 }
@@ -226,8 +225,8 @@ void PageCaptureSaveAsMHTMLFunction::TemporaryFileCreatedOnIO(bool success) {
              base::TaskShutdownBehavior::BLOCK_SHUTDOWN})
             .get());
   }
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&PageCaptureSaveAsMHTMLFunction::TemporaryFileCreatedOnUI,
                      this, success));
 }

chrome/browser/extensions/api/storage/managed_value_store_cache.cc

@@ -15,7 +15,6 @@
 #include "base/memory/weak_ptr.h"
 #include "base/one_shot_event.h"
 #include "base/scoped_observer.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/extensions/api/storage/policy_value_store.h"
 #include "chrome/browser/policy/profile_policy_connector.h"
 #include "chrome/browser/policy/schema_registry_service.h"
@@ -203,8 +202,8 @@ void ManagedValueStoreCache::ExtensionTracker::LoadSchemasOnFileTaskRunner(
     (*components)[(*it)->id()] = schema;
   }
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&ExtensionTracker::Register, self,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&ExtensionTracker::Register, self,
                                 base::Owned(components.release())));
 }
 

chrome/browser/extensions/blacklist.cc

@@ -14,7 +14,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/blacklist_factory.h"
@@ -87,8 +86,8 @@ class SafeBrowsingClientImpl
       const OnResultCallback& callback) {
     auto safe_browsing_client = base::WrapRefCounted(
         new SafeBrowsingClientImpl(extension_ids, callback));
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&SafeBrowsingClientImpl::StartCheck,
                        safe_browsing_client, g_database_manager.Get().get(),
                        extension_ids));

chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc

@@ -16,7 +16,6 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
 #include "base/strings/string_piece.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/component_loader.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ -685,8 +684,8 @@ void ChromeContentBrowserClientExtensionsPart::SiteInstanceGotProcess(
                                    site_instance->GetProcess()->GetID(),
                                    site_instance->GetId());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&InfoMap::RegisterExtensionProcess,
                      ExtensionSystem::Get(context)->info_map(), extension->id(),
                      site_instance->GetProcess()->GetID(),
@@ -710,8 +709,8 @@ void ChromeContentBrowserClientExtensionsPart::SiteInstanceDeleting(
                                    site_instance->GetProcess()->GetID(),
                                    site_instance->GetId());
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&InfoMap::UnregisterExtensionProcess,
                      ExtensionSystem::Get(context)->info_map(), extension->id(),
                      site_instance->GetProcess()->GetID(),

chrome/browser/extensions/crx_installer.cc

@@ -18,7 +18,6 @@
 #include "base/sequenced_task_runner.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "base/version.h"
@@ -499,8 +498,8 @@ void CrxInstaller::ShouldComputeHashesForOffWebstoreExtension(
     scoped_refptr<const Extension> extension,
     base::OnceCallback<void(bool)> callback) {
   DCHECK(installer_task_runner_->RunsTasksInCurrentSequence());
-  if (!base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+  if (!content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&CrxInstaller::ShouldComputeHashesOnUI, this,
                          std::move(extension), std::move(callback)))) {
     NOTREACHED();
@@ -564,8 +563,8 @@ void CrxInstaller::OnUnpackSuccess(
       (!expected_version_.IsValid() ||
        expected_version_ == extension->version())) {
     delete_source_ = false;
-    if (!base::PostTask(
-            FROM_HERE, {BrowserThread::UI},
+    if (!content::GetUIThreadTaskRunner({})->PostTask(
+            FROM_HERE,
             base::BindOnce(std::move(expectations_verified_callback_)))) {
       NOTREACHED();
     }
@@ -578,8 +577,8 @@ void CrxInstaller::OnUnpackSuccess(
     return;
   }
 
-  if (!base::PostTask(FROM_HERE, {BrowserThread::UI},
-                      base::BindOnce(&CrxInstaller::CheckInstall, this)))
+  if (!content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&CrxInstaller::CheckInstall, this)))
     NOTREACHED();
 }
 
@@ -937,9 +936,9 @@ void CrxInstaller::ReloadExtensionAfterInstall(
 
 void CrxInstaller::ReportFailureFromFileThread(const CrxInstallError& error) {
   DCHECK(installer_task_runner_->RunsTasksInCurrentSequence());
-  if (!base::PostTask(FROM_HERE, {BrowserThread::UI},
-                      base::BindOnce(&CrxInstaller::ReportFailureFromUIThread,
-                                     this, error))) {
+  if (!content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&CrxInstaller::ReportFailureFromUIThread,
+                                    this, error))) {
     NOTREACHED();
   }
 }
@@ -981,8 +980,8 @@ void CrxInstaller::ReportSuccessFromFileThread() {
   if (install_cause() == extension_misc::INSTALL_CAUSE_USER_DOWNLOAD)
     UMA_HISTOGRAM_ENUMERATION("Extensions.ExtensionInstalled", 1, 2);
 
-  if (!base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+  if (!content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&CrxInstaller::ReportSuccessFromUIThread, this)))
     NOTREACHED();
 
@@ -1080,9 +1079,8 @@ void CrxInstaller::NotifyCrxInstallComplete(
     ConfirmReEnable();
 
   if (!installer_callback_.is_null() &&
-      !base::CreateSingleThreadTaskRunner({BrowserThread::UI})
-           ->PostTask(FROM_HERE,
-                      base::BindOnce(std::move(installer_callback_), error))) {
+      !content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(std::move(installer_callback_), error))) {
     NOTREACHED();
   }
 }

chrome/browser/extensions/event_router_forwarder.cc

@@ -9,7 +9,6 @@
 #include <utility>
 
 #include "base/bind.h"
-#include "base/task/post_task.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
@@ -64,8 +63,8 @@ void EventRouterForwarder::HandleEvent(
     const GURL& event_url,
     bool dispatch_to_off_the_record_profiles) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&EventRouterForwarder::HandleEvent, this, extension_id,
                        histogram_value, event_name, std::move(event_args),
                        profile_ptr, use_profile_to_restrict_events, event_url,

chrome/browser/extensions/event_router_forwarder_unittest.cc

@@ -10,7 +10,6 @@
 #include "base/power_monitor/power_monitor.h"
 #include "base/power_monitor/power_monitor_device_source.h"
 #include "base/run_loop.h"
-#include "base/task/post_task.h"
 #include "base/test/thread_test_helper.h"
 #include "build/build_config.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -18,13 +17,12 @@
 #include "chrome/test/base/testing_profile.h"
 #include "chrome/test/base/testing_profile_manager.h"
 #include "content/public/browser/browser_task_traits.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/test/browser_task_environment.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
-using content::BrowserThread;
-
 namespace extensions {
 
 namespace {
@@ -170,14 +168,14 @@ TEST_F(EventRouterForwarderTest, BroadcastRendererIO) {
                                              kEventName, profile1_, url));
   EXPECT_CALL(*event_router, CallEventRouter(profile2_, "", kHistogramValue,
                                              kEventName, profile2_, url));
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&BroadcastEventToRenderers,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&BroadcastEventToRenderers,
                                 base::Unretained(event_router.get()),
                                 kHistogramValue, kEventName, url, false));
 
   // Wait for IO thread's message loop to be processed
-  scoped_refptr<base::ThreadTestHelper> helper(new base::ThreadTestHelper(
-      base::CreateSingleThreadTaskRunner({BrowserThread::IO}).get()));
+  scoped_refptr<base::ThreadTestHelper> helper(
+      new base::ThreadTestHelper(content::GetIOThreadTaskRunner({}).get()));
   ASSERT_TRUE(helper->Run());
 
   base::RunLoop().RunUntilIdle();

chrome/browser/extensions/extension_assets_manager_chromeos.cc

@@ -18,7 +18,6 @@
 #include "base/memory/singleton.h"
 #include "base/sequenced_task_runner.h"
 #include "base/system/sys_info.h"
-#include "base/task/post_task.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
@@ -162,8 +161,8 @@ void ExtensionAssetsManagerChromeOS::InstallExtension(
     return;
   }
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&ExtensionAssetsManagerChromeOS::CheckSharedExtension,
                      extension->id(), extension->VersionString(),
                      unpacked_extension_root, local_install_dir, profile,
@@ -183,8 +182,8 @@ void ExtensionAssetsManagerChromeOS::UninstallExtension(
   if (GetSharedInstallDir().IsParent(extension_root)) {
     // In some test extensions installed outside local_install_dir emulate
     // previous behavior that just do nothing in this case.
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(
             &ExtensionAssetsManagerChromeOS::MarkSharedExtensionUnused, id,
             profile));
@@ -350,8 +349,8 @@ void ExtensionAssetsManagerChromeOS::InstallSharedExtension(
   base::FilePath shared_install_dir = GetSharedInstallDir();
   base::FilePath shared_version_dir = file_util::InstallExtension(
       unpacked_extension_root, id, version, shared_install_dir);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &ExtensionAssetsManagerChromeOS::InstallSharedExtensionDone, id,
           version, shared_version_dir));

chrome/browser/extensions/extension_service.cc

@@ -26,7 +26,6 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/syslog_logging.h"
-#include "base/task/post_task.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
@@ -1957,8 +1956,8 @@ void ExtensionService::Observe(int type,
       }
 
       process_map->RemoveAllFromProcess(process->GetID());
-      base::PostTask(FROM_HERE, {BrowserThread::IO},
-                     base::BindOnce(&InfoMap::UnregisterAllExtensionsInProcess,
+      content::GetIOThreadTaskRunner({})->PostTask(
+          FROM_HERE, base::BindOnce(&InfoMap::UnregisterAllExtensionsInProcess,
                                     system_->info_map(), process->GetID()));
       break;
     }

chrome/browser/extensions/extension_special_storage_policy.cc

@@ -15,7 +15,6 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
-#include "base/task/post_task.h"
 #include "base/task/task_traits.h"
 #include "base/thread_annotations.h"
 #include "chrome/browser/content_settings/cookie_settings_factory.h"
@@ -74,8 +73,8 @@ class ExtensionSpecialStoragePolicy::CookieSettingsObserver
     // Post a task to avoid any potential re-entrancy issues with
     // |NotifyPolicyChangedImpl()| since it holds a lock while calling back into
     // ExtensionSpecialStoragePolicy.
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&CookieSettingsObserver::NotifyPolicyChangedImpl,
                        base::Unretained(this)));
   }
@@ -97,8 +96,7 @@ ExtensionSpecialStoragePolicy::ExtensionSpecialStoragePolicy(
     : cookie_settings_(cookie_settings),
       cookie_settings_observer_(
           new CookieSettingsObserver(cookie_settings_, this),
-          base::OnTaskRunnerDeleter(
-              base::CreateSequencedTaskRunner({BrowserThread::UI}))) {}
+          base::OnTaskRunnerDeleter(content::GetUIThreadTaskRunner({}))) {}
 
 ExtensionSpecialStoragePolicy::~ExtensionSpecialStoragePolicy() {
   cookie_settings_observer_->WillDestroyPolicy();
@@ -282,8 +280,8 @@ void ExtensionSpecialStoragePolicy::NotifyGranted(
     const GURL& origin,
     int change_flags) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(&ExtensionSpecialStoragePolicy::NotifyGranted,
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&ExtensionSpecialStoragePolicy::NotifyGranted,
                                   this, origin, change_flags));
     return;
   }
@@ -295,8 +293,8 @@ void ExtensionSpecialStoragePolicy::NotifyRevoked(
     const GURL& origin,
     int change_flags) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
-    base::PostTask(FROM_HERE, {BrowserThread::IO},
-                   base::BindOnce(&ExtensionSpecialStoragePolicy::NotifyRevoked,
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&ExtensionSpecialStoragePolicy::NotifyRevoked,
                                   this, origin, change_flags));
     return;
   }
@@ -306,8 +304,8 @@ void ExtensionSpecialStoragePolicy::NotifyRevoked(
 
 void ExtensionSpecialStoragePolicy::NotifyCleared() {
   if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::IO},
+    content::GetIOThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&ExtensionSpecialStoragePolicy::NotifyCleared, this));
     return;
   }

chrome/browser/extensions/extension_system_impl.cc

@@ -14,7 +14,6 @@
 #include "base/files/file_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string_tokenizer.h"
-#include "base/task/post_task.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
@@ -77,8 +76,6 @@
 #include "components/user_manager/user_manager.h"
 #endif
 
-using content::BrowserThread;
-
 namespace extensions {
 
 namespace {
@@ -499,8 +496,8 @@ void ExtensionSystemImpl::RegisterExtensionWithRequestContexts(
   notifications_disabled =
       !notifier_state_tracker->IsNotifierEnabled(notifier_id);
 
-  base::PostTaskAndReply(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTaskAndReply(
+      FROM_HERE,
       base::BindOnce(&InfoMap::AddExtension, info_map(),
                      base::RetainedRef(extension), install_time,
                      incognito_enabled, notifications_disabled),
@@ -510,8 +507,8 @@ void ExtensionSystemImpl::RegisterExtensionWithRequestContexts(
 void ExtensionSystemImpl::UnregisterExtensionWithRequestContexts(
     const std::string& extension_id,
     const UnloadedExtensionReason reason) {
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&InfoMap::RemoveExtension, info_map(),
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&InfoMap::RemoveExtension, info_map(),
                                 extension_id, reason));
 }
 

chrome/browser/extensions/external_pref_loader.cc

@@ -19,7 +19,6 @@
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "build/build_config.h"
 #include "chrome/browser/apps/user_type_filter.h"
 #include "chrome/browser/profiles/profile.h"
@@ -346,8 +345,8 @@ void ExternalPrefLoader::LoadOnFileThread() {
   if (!prefs->empty())
     CHECK(!base_path_.empty());
 
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&ExternalPrefLoader::LoadFinished, this,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&ExternalPrefLoader::LoadFinished, this,
                                 std::move(prefs)));
 }
 

chrome/browser/extensions/external_registry_loader_win.cc

@@ -16,7 +16,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/time/time.h"
 #include "base/values.h"
@@ -208,8 +207,8 @@ void ExternalRegistryLoader::LoadOnBlockingThread() {
   std::unique_ptr<base::DictionaryValue> prefs = LoadPrefsOnBlockingThread();
   LOCAL_HISTOGRAM_TIMES("Extensions.ExternalRegistryLoaderWin",
                         base::TimeTicks::Now() - start_time);
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(
           &ExternalRegistryLoader::CompleteLoadAndStartWatchingRegistry, this,
           std::move(prefs)));
@@ -284,8 +283,8 @@ void ExternalRegistryLoader::UpatePrefsOnBlockingThread() {
   std::unique_ptr<base::DictionaryValue> prefs = LoadPrefsOnBlockingThread();
   LOCAL_HISTOGRAM_TIMES("Extensions.ExternalRegistryLoaderWinUpdate",
                         base::TimeTicks::Now() - start_time);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&ExternalRegistryLoader::OnUpdated, this,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&ExternalRegistryLoader::OnUpdated, this,
                                 std::move(prefs)));
 }
 

chrome/browser/extensions/startup_helper.cc

@@ -12,7 +12,6 @@
 #include "base/single_thread_task_runner.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/initialize_extensions_client.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -109,16 +108,16 @@ class ValidateCrxHelper : public SandboxedUnpackerClient {
       declarative_net_request::RulesetChecksums ruleset_checksums) override {
     DCHECK(GetExtensionFileTaskRunner()->RunsTasksInCurrentSequence());
     success_ = true;
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&ValidateCrxHelper::FinishOnUIThread, this));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&ValidateCrxHelper::FinishOnUIThread, this));
   }
 
   void OnUnpackFailure(const CrxInstallError& error) override {
     DCHECK(GetExtensionFileTaskRunner()->RunsTasksInCurrentSequence());
     success_ = false;
     error_ = error.message();
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&ValidateCrxHelper::FinishOnUIThread, this));
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&ValidateCrxHelper::FinishOnUIThread, this));
   }
 
   void FinishOnUIThread() {

chrome/browser/extensions/unpacked_installer.cc

@@ -13,7 +13,6 @@
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "build/branding_buildflags.h"
 #include "chrome/browser/extensions/extension_management.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ -298,9 +297,10 @@ void UnpackedInstaller::GetAbsolutePath() {
   extension_path_ = base::MakeAbsoluteFilePath(extension_path_);
 
   // Set priority explicitly to avoid unwanted task priority inheritance.
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI, base::TaskPriority::USER_BLOCKING},
-      base::BindOnce(&UnpackedInstaller::CheckExtensionFileAccess, this));
+  content::GetUIThreadTaskRunner({base::TaskPriority::USER_BLOCKING})
+      ->PostTask(
+          FROM_HERE,
+          base::BindOnce(&UnpackedInstaller::CheckExtensionFileAccess, this));
 }
 
 void UnpackedInstaller::CheckExtensionFileAccess() {
@@ -322,16 +322,16 @@ void UnpackedInstaller::LoadWithFileAccess(int flags) {
   std::string error;
   if (!LoadExtension(Manifest::UNPACKED, flags, &error)) {
     // Set priority explicitly to avoid unwanted task priority inheritance.
-    base::PostTask(FROM_HERE,
-                   {BrowserThread::UI, base::TaskPriority::USER_BLOCKING},
+    content::GetUIThreadTaskRunner({base::TaskPriority::USER_BLOCKING})
+        ->PostTask(FROM_HERE,
                    base::BindOnce(&UnpackedInstaller::ReportExtensionLoadError,
                                   this, error));
     return;
   }
 
   // Set priority explicitly to avoid unwanted task priority inheritance.
-  base::PostTask(FROM_HERE,
-                 {BrowserThread::UI, base::TaskPriority::USER_BLOCKING},
+  content::GetUIThreadTaskRunner({base::TaskPriority::USER_BLOCKING})
+      ->PostTask(FROM_HERE,
                  base::BindOnce(&UnpackedInstaller::StartInstallChecks, this));
 }
 

chrome/browser/extensions/updater/extension_updater.cc

@@ -19,7 +19,6 @@
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/api/module/module.h"
 #include "chrome/browser/extensions/crx_installer.h"
@@ -51,8 +50,6 @@
 
 using base::RandDouble;
 using base::RandInt;
-using content::BrowserThread;
-
 typedef extensions::ExtensionDownloaderDelegate::Error Error;
 typedef extensions::ExtensionDownloaderDelegate::PingResult PingResult;
 
@@ -217,8 +214,8 @@ void ExtensionUpdater::ScheduleNextCheck() {
   const double jitter_factor = RandDouble() * 0.4 + 0.8;
   base::TimeDelta delay = base::TimeDelta::FromMilliseconds(
       static_cast<int64_t>(frequency_.InMilliseconds() * jitter_factor));
-  base::PostDelayedTask(FROM_HERE,
-                        {base::TaskPriority::BEST_EFFORT, BrowserThread::UI},
+  content::GetUIThreadTaskRunner({base::TaskPriority::BEST_EFFORT})
+      ->PostDelayedTask(FROM_HERE,
                         base::BindOnce(&ExtensionUpdater::NextCheck,
                                        weak_ptr_factory_.GetWeakPtr()),
                         delay);
@@ -235,8 +232,8 @@ void ExtensionUpdater::CheckSoon() {
   DCHECK(alive_);
   if (will_check_soon_)
     return;
-  if (base::PostTask(FROM_HERE,
-                     {base::TaskPriority::BEST_EFFORT, BrowserThread::UI},
+  if (content::GetUIThreadTaskRunner({base::TaskPriority::BEST_EFFORT})
+          ->PostTask(FROM_HERE,
                      base::BindOnce(&ExtensionUpdater::DoCheckSoon,
                                     weak_ptr_factory_.GetWeakPtr()))) {
     will_check_soon_ = true;

chrome/browser/file_select_helper.cc

@@ -14,7 +14,6 @@
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
@@ -578,8 +577,8 @@ void FileSelectHelper::GetFileTypesInThreadPool(FileChooserParamsPtr params) {
       params->need_local_path ? ui::SelectFileDialog::FileTypeInfo::NATIVE_PATH
                               : ui::SelectFileDialog::FileTypeInfo::ANY_PATH;
 
-  base::PostTask(
-      FROM_HERE, {BrowserThread::UI},
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&FileSelectHelper::GetSanitizedFilenameOnUIThread, this,
                      std::move(params)));
 }

chrome/browser/history/android/bookmark_model_sql_handler.cc

@@ -7,7 +7,6 @@
 #include "base/bind.h"
 #include "base/check.h"
 #include "base/stl_util.h"
-#include "base/task/post_task.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "components/bookmarks/browser/bookmark_model.h"
@@ -19,8 +18,6 @@
 using base::Time;
 using bookmarks::BookmarkModel;
 using bookmarks::BookmarkNode;
-using content::BrowserThread;
-
 namespace history {
 
 namespace {
@@ -111,15 +108,15 @@ bool BookmarkModelSQLHandler::Update(const HistoryAndBookmarkRow& row,
         if (!url_database_->GetURLRow(i->url_id, &url_row))
           return false;
         if (row.is_value_set_explicitly(HistoryAndBookmarkRow::PARENT_ID)) {
-          base::PostTask(
-              FROM_HERE, {BrowserThread::UI},
+          content::GetUIThreadTaskRunner({})->PostTask(
+              FROM_HERE,
               base::BindOnce(&BookmarkModelSQLHandler::Task::AddBookmark,
                              scoped_refptr<BookmarkModelSQLHandler::Task>(
                                  new BookmarkModelSQLHandler::Task()),
                              i->url, url_row.title(), row.parent_id()));
         } else {
-          base::PostTask(
-              FROM_HERE, {BrowserThread::UI},
+          content::GetUIThreadTaskRunner({})->PostTask(
+              FROM_HERE,
               base::BindOnce(
                   &BookmarkModelSQLHandler::Task::AddBookmarkToMobileFolder,
                   scoped_refptr<BookmarkModelSQLHandler::Task>(
@@ -127,16 +124,16 @@ bool BookmarkModelSQLHandler::Update(const HistoryAndBookmarkRow& row,
                   i->url, url_row.title()));
         }
       } else {
-        base::PostTask(
-            FROM_HERE, {BrowserThread::UI},
+        content::GetUIThreadTaskRunner({})->PostTask(
+            FROM_HERE,
             base::BindOnce(&BookmarkModelSQLHandler::Task::RemoveBookmark,
                            scoped_refptr<BookmarkModelSQLHandler::Task>(
                                new BookmarkModelSQLHandler::Task()),
                            i->url));
       }
     } else if (row.is_value_set_explicitly(HistoryAndBookmarkRow::TITLE)) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::UI},
+      content::GetUIThreadTaskRunner({})->PostTask(
+          FROM_HERE,
           base::BindOnce(&BookmarkModelSQLHandler::Task::UpdateBookmarkTitle,
                          scoped_refptr<BookmarkModelSQLHandler::Task>(
                              new BookmarkModelSQLHandler::Task()),
@@ -149,8 +146,8 @@ bool BookmarkModelSQLHandler::Update(const HistoryAndBookmarkRow& row,
 bool BookmarkModelSQLHandler::Delete(const TableIDRows& ids_set) {
   for (TableIDRows::const_iterator i = ids_set.begin();
        i != ids_set.end(); ++i) {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(&BookmarkModelSQLHandler::Task::RemoveBookmark,
                        scoped_refptr<BookmarkModelSQLHandler::Task>(
                            new BookmarkModelSQLHandler::Task()),
@@ -165,14 +162,14 @@ bool BookmarkModelSQLHandler::Insert(HistoryAndBookmarkRow* row) {
       !row->is_bookmark())
     return true;
   if (row->is_value_set_explicitly(HistoryAndBookmarkRow::PARENT_ID)) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&BookmarkModelSQLHandler::Task::AddBookmark,
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&BookmarkModelSQLHandler::Task::AddBookmark,
                                   scoped_refptr<BookmarkModelSQLHandler::Task>(
                                       new BookmarkModelSQLHandler::Task()),
                                   row->url(), row->title(), row->parent_id()));
   } else {
-    base::PostTask(
-        FROM_HERE, {BrowserThread::UI},
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE,
         base::BindOnce(
             &BookmarkModelSQLHandler::Task::AddBookmarkToMobileFolder,
             scoped_refptr<BookmarkModelSQLHandler::Task>(

chrome/browser/history/android/sqlite_cursor.cc

@@ -9,7 +9,6 @@
 #include "base/bind.h"
 #include "base/check_op.h"
 #include "base/notreached.h"
-#include "base/task/post_task.h"
 #include "chrome/android/chrome_jni_headers/SQLiteCursor_jni.h"
 #include "components/history/core/browser/android/android_history_types.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -127,8 +126,8 @@ jboolean SQLiteCursor::IsNull(JNIEnv* env,
 jint SQLiteCursor::MoveTo(JNIEnv* env,
                           const JavaParamRef<jobject>& obj,
                           jint pos) {
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(&SQLiteCursor::RunMoveStatementOnUIThread,
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&SQLiteCursor::RunMoveStatementOnUIThread,
                                 base::Unretained(this), pos));
   if (test_observer_)
     test_observer_->OnPostMoveToTask();
@@ -150,9 +149,9 @@ void SQLiteCursor::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   // objects out there.
   if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     DestroyOnUIThread();
-  } else if (!base::PostTask(FROM_HERE, {BrowserThread::UI},
-                             base::BindOnce(&SQLiteCursor::DestroyOnUIThread,
-                                            base::Unretained(this)))) {
+  } else if (!content::GetUIThreadTaskRunner({})->PostTask(
+                 FROM_HERE, base::BindOnce(&SQLiteCursor::DestroyOnUIThread,
+                                           base::Unretained(this)))) {
     delete this;
   }
 }
@@ -184,8 +183,8 @@ void SQLiteCursor::DestroyOnUIThread() {
 bool SQLiteCursor::GetFavicon(favicon_base::FaviconID id,
                               std::vector<unsigned char>* image_data) {
   if (id) {
-    base::PostTask(FROM_HERE, {BrowserThread::UI},
-                   base::BindOnce(&SQLiteCursor::GetFaviconForIDInUIThread,
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&SQLiteCursor::GetFaviconForIDInUIThread,
                                   base::Unretained(this), id,
                                   base::Bind(&SQLiteCursor::OnFaviconData,
                                              base::Unretained(this))));

chrome/browser/local_discovery/service_discovery_client_mdns.cc

@@ -12,7 +12,6 @@
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/macros.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/browser_process.h"
@@ -86,7 +85,8 @@ class ServiceDiscoveryClientMdns::Proxy {
   }
 
   static bool PostToUIThread(base::OnceClosure task) {
-    return base::PostTask(FROM_HERE, {BrowserThread::UI}, std::move(task));
+    return content::GetUIThreadTaskRunner({})->PostTask(FROM_HERE,
+                                                        std::move(task));
   }
 
   ServiceDiscoveryClient* client() {
@@ -149,8 +149,8 @@ void InitMdns(MdnsInitCallback on_initialized,
               const net::InterfaceIndexFamilyList& interfaces,
               net::MDnsClient* mdns) {
   SocketFactory socket_factory(interfaces);
-  base::PostTask(FROM_HERE, {BrowserThread::UI},
-                 base::BindOnce(std::move(on_initialized),
+  content::GetUIThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(std::move(on_initialized),
                                 mdns->StartListening(&socket_factory)));
 }
 
@@ -330,7 +330,7 @@ class LocalDomainResolverProxy : public ProxyBase<LocalDomainResolver> {
 }  // namespace
 
 ServiceDiscoveryClientMdns::ServiceDiscoveryClientMdns()
-    : mdns_runner_(base::CreateSingleThreadTaskRunner({BrowserThread::IO})) {
+    : mdns_runner_(content::GetIOThreadTaskRunner({})) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   content::GetNetworkConnectionTracker()->AddNetworkConnectionObserver(this);
   StartNewClient();

chrome/browser/media/cast_mirroring_service_host.cc

@@ -13,7 +13,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/optional.h"
 #include "base/single_thread_task_runner.h"
-#include "base/task/post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/browser_process.h"
@@ -262,15 +261,14 @@ gfx::Size CastMirroringServiceHost::GetClampedResolution(
 
 void CastMirroringServiceHost::BindGpu(
     mojo::PendingReceiver<viz::mojom::Gpu> receiver) {
-  gpu_client_ = content::CreateGpuClient(
-      std::move(receiver), base::DoNothing(),
-      base::CreateSingleThreadTaskRunner({BrowserThread::IO}));
+  gpu_client_ = content::CreateGpuClient(std::move(receiver), base::DoNothing(),
+                                         content::GetIOThreadTaskRunner({}));
 }
 
 void CastMirroringServiceHost::GetVideoCaptureHost(
     mojo::PendingReceiver<media::mojom::VideoCaptureHost> receiver) {
-  base::PostTask(
-      FROM_HERE, {BrowserThread::IO},
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE,
       base::BindOnce(&CreateVideoCaptureHostOnIO, source_media_id_.ToString(),
                      ConvertVideoStreamType(source_media_id_.type),
                      std::move(receiver)));

chrome/browser/media/router/discovery/dial/dial_registry.cc

@@ -10,7 +10,6 @@
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
-#include "base/task/post_task.h"
 #include "base/time/default_clock.h"
 #include "base/time/time.h"
 #include "base/values.h"
@@ -50,9 +49,8 @@ DialRegistry::DialRegistry()
       clock_(base::DefaultClock::GetInstance()) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_GT(max_devices_, 0U);
-  base::PostTaskAndReplyWithResult(
-      FROM_HERE, {BrowserThread::UI},
-      base::BindOnce(&content::GetNetworkConnectionTracker),
+  content::GetUIThreadTaskRunner({})->PostTaskAndReplyWithResult(
+      FROM_HERE, base::BindOnce(&content::GetNetworkConnectionTracker),
       base::BindOnce(&DialRegistry::SetNetworkConnectionTracker,
                      base::Unretained(this)));
 }

chrome/browser/media/router/discovery/dial/dial_service.cc

@@ -16,7 +16,6 @@
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
-#include "base/task/post_task.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/browser/media/router/discovery/dial/dial_device_data.h"
@@ -62,8 +61,8 @@ void PostSendNetworkList(
     base::WeakPtr<DialServiceImpl> impl,
     const base::Optional<net::NetworkInterfaceList>& networks) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  base::PostTask(FROM_HERE, {BrowserThread::IO},
-                 base::BindOnce(&DialServiceImpl::SendNetworkList,
+  content::GetIOThreadTaskRunner({})->PostTask(
+      FROM_HERE, base::BindOnce(&DialServiceImpl::SendNetworkList,
                                 std::move(impl), networks));
 }
 #endif  // !defined(OS_CHROMEOS)
@@ -461,7 +460,7 @@ void DialServiceImpl::StartDiscovery() {
     return;
   }
 
-  auto task_runner = base::CreateSingleThreadTaskRunner({BrowserThread::UI});
+  auto task_runner = content::GetUIThreadTaskRunner({});
 
 #if defined(OS_CHROMEOS)
   task_tracker_.PostTaskAndReplyWithResult(