Add ServiceWorkerAutoPreload to chrome://flags

Adding the ServiceWorkerAutoPreload feature flags to chrome://flags, so
that developers and partners can try the feature on their sides.

To add it to chrome://flags, the feature flag
`kServiceWorkerAutoPreload` will be moved from content/common/features
to content/public/common/content_features.

Bug: 379052301
Change-Id: I30300642e4df4fa1c23feff758b16dff3b20417e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6022204
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Reviewed-by: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Commit-Queue: Shunya Shishido <sisidovski@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1383435}

chrome/browser/about_flags.cc

@@ -4248,6 +4248,15 @@ const FeatureEntry::FeatureVariation
 #endif  // BUILDFLAG(IS_ANDROID) && PA_BUILDFLAG(HAS_MEMORY_TAGGING) &&
         // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
 
+const FeatureEntry::FeatureParam kServiceWorkerAutoPreload_SWNotRunningOnly[] =
+    {
+        {"enable_only_when_service_worker_not_running", "true"},
+};
+const FeatureEntry::FeatureVariation kServiceWorkerAutoPreloadVariations[] = {
+    {"only when SW is not running", kServiceWorkerAutoPreload_SWNotRunningOnly,
+     std::size(kServiceWorkerAutoPreload_SWNotRunningOnly), nullptr},
+};
+
 // RECORDING USER METRICS FOR FLAGS:
 // -----------------------------------------------------------------------------
 // The first line of the entry is the internal name.
@@ -11831,6 +11840,13 @@ const FeatureEntry kFeatureEntries[] = {
      kOsMac | kOsWin | kOsLinux, FEATURE_VALUE_TYPE(features::kGlic)},
 #endif // ENABLE_GLIC
 
+    {"service-worker-auto-preload",
+     flag_descriptions::kServiceWorkerAutoPreloadName,
+     flag_descriptions::kServiceWorkerAutoPreloadDescription, kOsAll,
+     FEATURE_WITH_PARAMS_VALUE_TYPE(features::kServiceWorkerAutoPreload,
+                                    kServiceWorkerAutoPreloadVariations,
+                                    "ServiceWorkerAutoPreload")},
+
     // NOTE: Adding a new flag requires adding a corresponding entry to enum
     // "LoginCustomFlags" in tools/metrics/histograms/enums.xml. See "Flag
     // Histograms" in tools/metrics/histograms/README.md (run the

chrome/browser/flag-metadata.json

@@ -7948,6 +7948,11 @@
     "owners": ["tbarzic@chromium.org", "owenzhang@google.com"],
     "expiry_milestone": 130
   },
+  {
+    "name": "service-worker-auto-preload",
+    "owners": ["sisidovski@chromium.org", "chrome-worker@google.com"],
+    "expiry_milestone": 136
+  },
   {
     "name": "set-market-url-for-testing",
     "owners": [ "//chrome/android/java/src/org/chromium/chrome/browser/omaha/OWNERS" ],

chrome/browser/flag_descriptions.cc

@@ -3462,6 +3462,12 @@ const char kSegmentationSurveyPageName[] =
 const char kSegmentationSurveyPageDescription[] =
     "Enable internals page for survey and fetching model";
 
+const char kServiceWorkerAutoPreloadName[] = "ServiceWorkerAutoPreload";
+const char kServiceWorkerAutoPreloadDescription[] =
+    "Dispatches a preload request for navigation before starting the service "
+    "worker. See "
+    "https://github.com/explainers-by-googlers/service-worker-auto-preload";
+
 const char kSharedZstdName[] = "Shared Zstd";
 const char kSharedZstdDescription[] =
     "Enables compression dictionary transport with Zstandard (aka Shared "

chrome/browser/flag_descriptions.h

@@ -1972,6 +1972,9 @@ extern const char kSecurePaymentConfirmationNetworkAndIssuerIconsDescription[];
 extern const char kSegmentationSurveyPageName[];
 extern const char kSegmentationSurveyPageDescription[];
 
+extern const char kServiceWorkerAutoPreloadName[];
+extern const char kServiceWorkerAutoPreloadDescription[];
+
 extern const char kSharedZstdName[];
 extern const char kSharedZstdDescription[];
 

content/common/features.cc

@@ -504,19 +504,6 @@ BASE_FEATURE(kRunStableVideoDecoderFactoryProcessServiceOnIOThread,
              "RunStableVideoDecoderFactoryProcessServiceOnIOThread",
              base::FEATURE_ENABLED_BY_DEFAULT);
 
-// Enables auto preloading for fetch requests before invoking the fetch handler
-// in ServiceWorker. The fetch request inside the fetch handler is resolved with
-// this preload response. If the fetch handler result is fallback, uses this
-// preload request as a fallback network request.
-//
-// Unlike navigation preload, this preloading is applied to subresources. Also,
-// it doesn't require a developer opt-in.
-//
-// crbug.com/1472634 for more details.
-BASE_FEATURE(kServiceWorkerAutoPreload,
-             "ServiceWorkerAutoPreload",
-             base::FEATURE_DISABLED_BY_DEFAULT);
-
 BASE_FEATURE(kServiceWorkerAvoidMainThreadForInitialization,
              "ServiceWorkerAvoidMainThreadForInitialization",
 #if BUILDFLAG(IS_ANDROID)

content/common/features.h

@@ -123,7 +123,6 @@ CONTENT_EXPORT BASE_DECLARE_FEATURE(
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kRemoveRendererProcessLimit);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kReuseInitialRenderFrameHostForWebUI);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kSendBeaconThrowForBlobWithNonSimpleType);
-CONTENT_EXPORT BASE_DECLARE_FEATURE(kServiceWorkerAutoPreload);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(
     kServiceWorkerAvoidMainThreadForInitialization);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(

content/common/service_worker/race_network_request_read_buffer_manager.cc

@@ -13,7 +13,7 @@
 #include "base/containers/span.h"
 #include "base/memory/scoped_refptr.h"
 #include "base/metrics/field_trial_params.h"
-#include "content/common/features.h"
+#include "content/public/common/content_features.h"
 #include "mojo/public/c/system/types.h"
 #include "net/base/io_buffer.h"
 #include "services/network/public/cpp/features.h"

content/common/service_worker/race_network_request_write_buffer_manager.cc

@@ -12,8 +12,8 @@
 #include "base/containers/span.h"
 #include "base/metrics/field_trial_params.h"
 #include "base/system/sys_info.h"
-#include "content/common/features.h"
 #include "content/common/service_worker/race_network_request_url_loader_client.h"
+#include "content/public/common/content_features.h"
 #include "mojo/public/cpp/system/data_pipe.h"
 #include "mojo/public/cpp/system/simple_watcher.h"
 #include "services/network/public/cpp/features.h"

content/common/service_worker/service_worker_resource_loader.cc

@@ -8,7 +8,7 @@
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event.h"
-#include "content/common/features.h"
+#include "content/public/common/content_features.h"
 #include "services/network/public/mojom/service_worker_router_info.mojom-shared.h"
 
 namespace content {

content/public/common/content_features.cc

@@ -957,6 +957,19 @@ constexpr base::FeatureParam<double> kProcessPerSiteMainFrameTotalMemoryLimit{
     &kProcessPerSiteUpToMainFrameThreshold,
     "ProcessPerSiteMainFrameTotalMemoryLimit", 2 * 1024 * 1024 * 1024u};
 
+// Enables auto preloading for fetch requests before invoking the fetch handler
+// in ServiceWorker. The fetch request inside the fetch handler is resolved with
+// this preload response. If the fetch handler result is fallback, uses this
+// preload request as a fallback network request.
+//
+// Unlike navigation preload, this preloading is applied to subresources. Also,
+// it doesn't require a developer opt-in.
+//
+// crbug.com/1472634 for more details.
+BASE_FEATURE(kServiceWorkerAutoPreload,
+             "ServiceWorkerAutoPreload",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+
 // Enables ServiceWorker static routing API.
 // https://github.com/WICG/service-worker-static-routing-api
 BASE_FEATURE(kServiceWorkerStaticRouter,

content/public/common/content_features.h

@@ -247,6 +247,7 @@ extern const base::FeatureParam<SkiaFontServiceTypefaceType>
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kUtilityWithUiPumpInitializesCom);
 #endif  // BUILDFLAG(IS_WIN)
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kDisableProcessReuse);
+CONTENT_EXPORT BASE_DECLARE_FEATURE(kServiceWorkerAutoPreload);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kServiceWorkerStaticRouter);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(
     kServiceWorkerStaticRouterRaceNetworkRequestPerformanceImprovement);

tools/metrics/histograms/enums.xml

@@ -18087,6 +18087,7 @@ from previous Chrome versions.
   <int value="-885209667" label="FilesZipMount:disabled"/>
   <int value="-884864731" label="WebPaymentsSingleAppUiSkip:enabled"/>
   <int value="-884783216" label="ForceEnableFastCheckoutCapabilities:enabled"/>
+  <int value="-884480360" label="ServiceWorkerAutoPreload:disabled"/>
   <int value="-884142134" label="TaskManagerDesktopRefresh:enabled"/>
   <int value="-883694393" label="SyncPseudoUSSSupervisedUsers:disabled"/>
   <int value="-883608641" label="enable-cros-action-recorder"/>
@@ -24902,6 +24903,7 @@ from previous Chrome versions.
   <int value="1843847665" label="SyncPromoAfterSigninIntercept:disabled"/>
   <int value="1844110073" label="enable-app-view"/>
   <int value="1844222711" label="AssistantConsentV2:disabled"/>
+  <int value="1845138535" label="ServiceWorkerAutoPreload:enabled"/>
   <int value="1845205143" label="ShowSuggestionsOnAutofocus:disabled"/>
   <int value="1845781020" label="DesktopSharePreview:disabled"/>
   <int value="1846717591" label="CaptureMode:disabled"/>