Move blink::WebView::SetBaseBackgroundColor to content

There are various embedders that directly call
WebView::SetBaseBackgroundColor for various purpose, which involves
running their own IPC on top of content and has to deal with various
lifetime complexities. Remove WebView::SetBaseBackgroundColor and add
it to WebContents, and move embedders to call WebContents instead.

Bug: 1138800, 1204793
Change-Id: I41f485ef653af8d47f73c76c0b3658b3dc9ceb37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2695928
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Sean Topping <seantopping@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#891867}

android_webview/browser/aw_contents.cc

@@ -1131,7 +1131,7 @@ void AwContents::SetBackgroundColor(JNIEnv* env,
                                     const JavaParamRef<jobject>& obj,
                                     jint color) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  render_view_host_ext_->SetBackgroundColor(color);
+  web_contents_->SetPageBaseBackgroundColor(color);
 }
 
 void AwContents::ZoomBy(JNIEnv* env,

android_webview/browser/renderer_host/aw_render_view_host_ext.cc

@@ -56,7 +56,6 @@ AwRenderViewHostExt::AwRenderViewHostExt(AwRenderViewHostExtClient* client,
                                          content::WebContents* contents)
     : content::WebContentsObserver(contents),
       client_(client),
-      background_color_(SK_ColorWHITE),
       has_new_hit_test_data_(false),
       frame_host_receivers_(contents, this) {
   DCHECK(client_);
@@ -124,15 +123,6 @@ void AwRenderViewHostExt::SetInitialPageScale(double page_scale_factor) {
     local_main_frame_remote_->SetInitialPageScale(page_scale_factor);
 }
 
-void AwRenderViewHostExt::SetBackgroundColor(SkColor c) {
-  if (background_color_ == c)
-    return;
-  background_color_ = c;
-  if (local_main_frame_remote_) {
-    local_main_frame_remote_->SetBackgroundColor(background_color_);
-  }
-}
-
 void AwRenderViewHostExt::SetWillSuppressErrorPage(bool suppress) {
   will_suppress_error_page_ = suppress;
 }
@@ -149,8 +139,6 @@ void AwRenderViewHostExt::ResetLocalMainFrameRemote(
   local_main_frame_remote_.reset();
   frame_host->GetRemoteAssociatedInterfaces()->GetInterface(
       local_main_frame_remote_.BindNewEndpointAndPassReceiver());
-
-  local_main_frame_remote_->SetBackgroundColor(background_color_);
 }
 
 void AwRenderViewHostExt::RenderFrameCreated(

android_webview/browser/renderer_host/aw_render_view_host_ext.h

@@ -70,7 +70,6 @@ class AwRenderViewHostExt : public content::WebContentsObserver,
   // Sets the initial page scale. This overrides initial scale set by
   // the meta viewport tag.
   void SetInitialPageScale(double page_scale_factor);
-  void SetBackgroundColor(SkColor c);
   void SetWillSuppressErrorPage(bool suppress);
 
   void SmoothScroll(int target_x, int target_y, base::TimeDelta duration);
@@ -103,8 +102,6 @@ class AwRenderViewHostExt : public content::WebContentsObserver,
 
   AwRenderViewHostExtClient* client_;
 
-  SkColor background_color_;
-
   // Authoritative copy of hit test data on the browser side. This is updated
   // as a result of DoHitTest called explicitly or when the FocusedNodeChanged
   // is called in AwRenderViewExt.

android_webview/common/mojom/frame.mojom

@@ -79,9 +79,6 @@ struct HitTestData {
 // things that webview needs from the main frame.
 interface LocalMainFrame {
 
-  // Sets the base background color for this view.
-  SetBackgroundColor(skia.mojom.SkColor color);
-
   // Sets the initial page scale. This overrides initial scale set by
   // the meta viewport tag.
   SetInitialPageScale(double page_scale_factor);

android_webview/renderer/aw_render_frame_ext.cc

@@ -286,14 +286,6 @@ void AwRenderFrameExt::HitTest(const gfx::PointF& touch_center,
   GetFrameHost()->UpdateHitTestData(std::move(data));
 }
 
-void AwRenderFrameExt::SetBackgroundColor(SkColor c) {
-  blink::WebView* webview = GetWebView();
-  if (!webview)
-    return;
-
-  webview->SetBaseBackgroundColor(c);
-}
-
 void AwRenderFrameExt::SetInitialPageScale(double page_scale_factor) {
   blink::WebView* webview = GetWebView();
   if (!webview)

android_webview/renderer/aw_render_frame_ext.h

@@ -48,7 +48,6 @@ class AwRenderFrameExt : public content::RenderFrameObserver,
   void OnDestruct() override;
 
   // mojom::LocalMainFrame overrides:
-  void SetBackgroundColor(SkColor c) override;
   void SetInitialPageScale(double page_scale_factor) override;
   void SetTextZoomFactor(float zoom_factor) override;
   void HitTest(const gfx::PointF& touch_center,

chromecast/browser/cast_web_contents_impl.cc

@@ -170,6 +170,9 @@ CastWebContentsImpl::CastWebContentsImpl(content::WebContents* web_contents,
     web_contents_->GetMutableRendererPrefs()
         ->webrtc_allow_legacy_tls_protocols = true;
   }
+
+  web_contents_->SetPageBaseBackgroundColor(chromecast::GetSwitchValueColor(
+      switches::kCastAppBackgroundColor, SK_ColorBLACK));
 }
 
 CastWebContentsImpl::~CastWebContentsImpl() {

chromecast/renderer/cast_content_renderer_client.cc

@@ -163,8 +163,6 @@ void CastContentRendererClient::RenderThreadStarted() {
 }
 
 void CastContentRendererClient::WebViewCreated(blink::WebView* webview) {
-  webview->SetBaseBackgroundColor(chromecast::GetSwitchValueColor(
-      switches::kCastAppBackgroundColor, SK_ColorBLACK));
   // Disable application cache as Chromecast doesn't support off-line
   // application running.
   webview->GetSettings()->SetOfflineWebApplicationCacheEnabled(false);

components/plugins/renderer/webview_plugin.cc

@@ -274,7 +274,8 @@ WebViewPlugin::WebViewHelper::WebViewHelper(
                       /*widgets_never_composited=*/false,
                       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),
                       *agent_group_scheduler_,
-                      /*session_storage_namespace_id=*/base::EmptyString());
+                      /*session_storage_namespace_id=*/base::EmptyString(),
+                      /*page_base_background_color=*/absl::nullopt);
   // ApplyWebPreferences before making a WebLocalFrame so that the frame sees a
   // consistent view of our preferences.
   blink::WebView::ApplyWebPreferences(parent_web_preferences, web_view_);

components/printing/renderer/print_render_frame_helper.cc

@@ -672,7 +672,8 @@ void PrintRenderFrameHelper::PrintHeaderAndFooter(
       /*compositing_enabled=*/false, /*widgets_never_composited=*/false,
       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),
       *source_frame.GetAgentGroupScheduler(),
-      /*session_storage_namespace_id=*/base::EmptyString());
+      /*session_storage_namespace_id=*/base::EmptyString(),
+      /*page_base_background_color=*/absl::nullopt);
   web_view->GetSettings()->SetJavaScriptEnabled(true);
 
   class HeaderAndFooterClient final : public blink::WebLocalFrameClient {
@@ -951,7 +952,8 @@ void PrepareFrameAndViewForPrint::CopySelection(
       /*widgets_never_composited=*/false,
       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),
       agent_group_scheduler_,
-      /*session_storage_namespace_id=*/base::EmptyString());
+      /*session_storage_namespace_id=*/base::EmptyString(),
+      /*page_base_background_color=*/absl::nullopt);
   blink::WebView::ApplyWebPreferences(prefs, web_view);
   blink::WebLocalFrame* main_frame = blink::WebLocalFrame::CreateMainFrame(
       web_view, this, nullptr, blink::LocalFrameToken(), nullptr);

content/browser/renderer_host/navigation_controller_impl_unittest.cc

@@ -120,6 +120,10 @@ class MockPageBroadcast : public blink::mojom::PageBroadcast {
               SetHistoryOffsetAndLength,
               (int32_t offset, int32_t length),
               (override));
+  MOCK_METHOD(void,
+              SetPageBaseBackgroundColor,
+              (absl::optional<SkColor> color),
+              (override));
 
   mojo::PendingAssociatedRemote<blink::mojom::PageBroadcast> GetRemote() {
     return receiver_.BindNewEndpointAndPassDedicatedRemote();

content/browser/renderer_host/render_view_host_delegate.cc

@@ -39,4 +39,8 @@ bool RenderViewHostDelegate::IsPortal() {
   return false;
 }
 
+absl::optional<SkColor> RenderViewHostDelegate::GetBaseBackgroundColor() {
+  return absl::nullopt;
+}
+
 }  // namespace content

content/browser/renderer_host/render_view_host_delegate.h

@@ -13,6 +13,8 @@
 #include "content/common/content_export.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
 #include "net/base/load_states.h"
+#include "third_party/abseil-cpp/absl/types/optional.h"
+#include "third_party/skia/include/core/SkColor.h"
 
 namespace blink {
 namespace web_pref {
@@ -143,6 +145,11 @@ class CONTENT_EXPORT RenderViewHostDelegate {
   // changed.
   virtual void OnBackgroundColorChanged(RenderViewHostImpl* source) {}
 
+  // Called on RenderView creation to get the initial base background color
+  // for this RenderView. Nullopt means a color is not set, and the blink
+  // default color should be used.
+  virtual absl::optional<SkColor> GetBaseBackgroundColor();
+
  protected:
   virtual ~RenderViewHostDelegate() {}
 };

content/browser/renderer_host/render_view_host_impl.cc

@@ -476,6 +476,7 @@ bool RenderViewHostImpl::CreateRenderView(
   params->hidden = frame_tree_->delegate()->IsHidden();
   params->never_composited = delegate_->IsNeverComposited();
   params->window_was_created_with_opener = window_was_created_with_opener;
+  params->base_background_color = delegate_->GetBaseBackgroundColor();
 
   bool is_portal = delegate_->IsPortal();
   bool is_guest_view = delegate_->IsGuest();

content/browser/web_contents/web_contents_impl.cc

@@ -1502,6 +1502,21 @@ absl::optional<SkColor> WebContentsImpl::GetBackgroundColor() {
   return GetRenderViewHost()->background_color();
 }
 
+void WebContentsImpl::SetPageBaseBackgroundColor(
+    absl::optional<SkColor> color) {
+  if (page_base_background_color_ == color)
+    return;
+  page_base_background_color_ = color;
+  ExecutePageBroadcastMethod(base::BindRepeating(
+      [](absl::optional<SkColor> color, RenderViewHostImpl* rvh) {
+        // Null `broadcast` can happen before view is created on the renderer
+        // side, in which case this color will be sent in CreateView.
+        if (auto& broadcast = rvh->GetAssociatedPageBroadcast())
+          broadcast->SetPageBaseBackgroundColor(color);
+      },
+      page_base_background_color_));
+}
+
 void WebContentsImpl::SetAccessibilityMode(ui::AXMode mode) {
   OPTIONAL_TRACE_EVENT2("content", "WebContentsImpl::SetAccessibilityMode",
                         "mode", mode.ToString(), "previous_mode",
@@ -5858,6 +5873,10 @@ void WebContentsImpl::RecomputeWebPreferencesSlow() {
   OnWebPreferencesChanged();
 }
 
+absl::optional<SkColor> WebContentsImpl::GetBaseBackgroundColor() {
+  return page_base_background_color_;
+}
+
 void WebContentsImpl::PrintCrossProcessSubframe(
     const gfx::Rect& rect,
     int document_cookie,

content/browser/web_contents/web_contents_impl.h

@@ -364,6 +364,7 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
   void ClosePage() override;
   absl::optional<SkColor> GetThemeColor() override;
   absl::optional<SkColor> GetBackgroundColor() override;
+  void SetPageBaseBackgroundColor(absl::optional<SkColor> color) override;
   WebUI* GetWebUI() override;
   WebUI* GetCommittedWebUI() override;
   void SetUserAgentOverride(const blink::UserAgentOverride& ua_override,
@@ -858,6 +859,7 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
   void OnThemeColorChanged(RenderViewHostImpl* source) override;
   void OnBackgroundColorChanged(RenderViewHostImpl* source) override;
   void RecomputeWebPreferencesSlow() override;
+  absl::optional<SkColor> GetBaseBackgroundColor() override;
 
   // NavigatorDelegate ---------------------------------------------------------
 
@@ -2208,6 +2210,12 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
   // information to apps that capture it.
   blink::mojom::CaptureHandleConfig capture_handle_config_;
 
+  // Background color of the page set by the embedder to be passed to all
+  // renderers attached to this WebContents, for use in the main frame.
+  // It is used when the page has not loaded enough to know a background
+  // color or if the page does not set a background color.
+  absl::optional<SkColor> page_base_background_color_;
+
   base::WeakPtrFactory<WebContentsImpl> loading_weak_factory_{this};
   base::WeakPtrFactory<WebContentsImpl> weak_factory_{this};
 

content/common/frame.mojom

@@ -17,6 +17,7 @@ import "mojo/public/mojom/base/string16.mojom";
 import "mojo/public/mojom/base/time.mojom";
 import "mojo/public/mojom/base/unguessable_token.mojom";
 import "mojo/public/mojom/base/values.mojom";
+import "skia/public/mojom/skcolor.mojom";
 import "services/network/public/mojom/content_security_policy.mojom";
 import "services/network/public/mojom/url_loader.mojom";
 import "services/network/public/mojom/url_loader_factory.mojom";
@@ -127,6 +128,9 @@ struct CreateViewParams {
 
   // Endpoint for any messages that are broadcast to all views in a WebContents.
   pending_associated_receiver<blink.mojom.PageBroadcast> blink_page_broadcast;
+
+  // Base background color of this view. Only used by a local main frame.
+  skia.mojom.SkColor? base_background_color;
 };
 
 // A union to distinguish between parameters specific to local main frame

content/public/browser/web_contents.h

@@ -413,6 +413,19 @@ class WebContents : public PageNavigator,
   // any.
   virtual absl::optional<SkColor> GetBackgroundColor() = 0;
 
+  // Sets the renderer-side default background color of the page. This is used
+  // when the page has not loaded enough to know a background color or if the
+  // page does not set a background color.
+  // Pass in nullopt to reset back to the default.
+  // Note there are situations where the base background color is not used, such
+  // as fullscreen.
+  // Note currently this is sent directly to the renderer, so does not interact
+  // directly with `RenderWidgetHostView::SetBackgroundColor`. There is pending
+  // refactor to remove `RenderWidgetHostView::SetBackgroundColor` and merge its
+  // functionality here, which will be more consistent and simpler to
+  // understand.
+  virtual void SetPageBaseBackgroundColor(absl::optional<SkColor> color) = 0;
+
   // Returns the committed WebUI if one exists, otherwise the pending one.
   virtual WebUI* GetWebUI() = 0;
   virtual WebUI* GetCommittedWebUI() = 0;

content/renderer/render_view_impl.cc

@@ -120,7 +120,7 @@ void RenderViewImpl::Initialize(
       opener_frame ? opener_frame->View() : nullptr,
       std::move(params->blink_page_broadcast),
       agent_scheduling_group_.agent_group_scheduler(),
-      params->session_storage_namespace_id);
+      params->session_storage_namespace_id, params->base_background_color);
 
   g_view_map.Get().insert(std::make_pair(GetWebView(), this));
   g_routing_id_view_map.Get().insert(std::make_pair(GetRoutingID(), this));

extensions/renderer/scoped_web_frame.cc

@@ -27,7 +27,8 @@ ScopedWebFrame::ScopedWebFrame()
           /*opener=*/nullptr,
           mojo::NullAssociatedReceiver(),
           *agent_group_scheduler_,
-          /*session_storage_namespace_id=*/base::EmptyString())),
+          /*session_storage_namespace_id=*/base::EmptyString(),
+          /*page_base_background_color=*/absl::nullopt)),
       frame_(blink::WebLocalFrame::CreateMainFrame(view_,
                                                    &frame_client_,
                                                    nullptr,

fuchsia/engine/browser/frame_impl.cc

@@ -293,6 +293,7 @@ FrameImpl::FrameImpl(std::unique_ptr<content::WebContents> web_contents,
   WebContentsToFrameImplMap()[web_contents_.get()] = this;
 
   web_contents_->SetDelegate(this);
+  web_contents_->SetPageBaseBackgroundColor(SK_AlphaTRANSPARENT);
   Observe(web_contents_.get());
 
   binding_.set_error_handler([this](zx_status_t status) {

fuchsia/engine/renderer/web_engine_content_renderer_client.cc

@@ -137,13 +137,6 @@ void WebEngineContentRendererClient::RenderThreadStarted() {
 
 void WebEngineContentRendererClient::RenderFrameCreated(
     content::RenderFrame* render_frame) {
-  // If this is a top-level frame then it should have a transparent background.
-  // Both the RenderView and WebView should be guaranteed to be non-null, since
-  // the |render_frame| was only just created.
-  if (render_frame->IsMainFrame()) {
-    render_frame->GetWebView()->SetBaseBackgroundColor(SK_AlphaTRANSPARENT);
-  }
-
   // Add WebEngine services to the new RenderFrame.
   // The objects' lifetimes are bound to the RenderFrame's lifetime.
   new on_load_script_injector::OnLoadScriptInjector(render_frame);

media/blink/webmediaplayer_impl_unittest.cc

@@ -326,7 +326,8 @@ class WebMediaPlayerImplTest
             /*opener=*/nullptr,
             mojo::NullAssociatedReceiver(),
             *agent_group_scheduler,
-            /*session_storage_namespace_id=*/base::EmptyString())),
+            /*session_storage_namespace_id=*/base::EmptyString(),
+            /*page_base_background_color=*/absl::nullopt)),
         web_local_frame_(
             blink::WebLocalFrame::CreateMainFrame(web_view_,
                                                   &web_frame_client_,

third_party/blink/public/mojom/page/page.mojom

@@ -4,6 +4,7 @@
 
 module blink.mojom;
 import "mojo/public/mojom/base/time.mojom";
+import "skia/public/mojom/skcolor.mojom";
 import "third_party/blink/public/mojom/page/page_visibility_state.mojom";
 import "third_party/blink/public/mojom/webpreferences/web_preferences.mojom";
 import "third_party/blink/public/mojom/renderer_preferences.mojom";
@@ -73,4 +74,7 @@ interface PageBroadcast {
 
   // Set history offset and length.
   SetHistoryOffsetAndLength(int32 offset, int32 length);
+
+  // Sent to whole page, but should only be used by the main frame.
+  SetPageBaseBackgroundColor(skia.mojom.SkColor? color);
 };

third_party/blink/public/mojom/page/widget.mojom

@@ -13,6 +13,7 @@ import "services/viz/public/mojom/compositing/compositor_frame_sink.mojom";
 import "services/viz/public/mojom/compositing/local_surface_id.mojom";
 import "services/viz/public/mojom/hit_test/input_target_client.mojom";
 import "skia/public/mojom/bitmap.mojom";
+import "skia/public/mojom/skcolor.mojom";
 import "third_party/blink/public/mojom/frame/intrinsic_sizing_info.mojom";
 import "third_party/blink/public/mojom/frame/viewport_intersection_state.mojom";
 import "third_party/blink/public/mojom/input/input_handler.mojom";

third_party/blink/public/web/web_view.h

@@ -114,6 +114,9 @@ class WebView {
   // to inform blink it is in the foreground or background. Whereas this bit
   // refers to user-visibility and whether the tab needs to produce pixels to
   // put on the screen at some point or not.
+  // |page_base_background_color| initial base background color used by the main
+  // frame. Set on create to avoid races. Passing in nullopt indicates the
+  // default base background color should be used.
   // TODO(yuzus): Remove |is_hidden| and start using |PageVisibilityState|.
   BLINK_EXPORT static WebView* Create(
       WebViewClient*,
@@ -125,7 +128,8 @@ class WebView {
       CrossVariantMojoAssociatedReceiver<mojom::PageBroadcastInterfaceBase>
           page_handle,
       scheduler::WebAgentGroupScheduler& agent_group_scheduler,
-      const SessionStorageNamespaceId& session_storage_namespace_id);
+      const SessionStorageNamespaceId& session_storage_namespace_id,
+      absl::optional<SkColor> page_base_background_color);
 
   // Destroys the WebView.
   virtual void Close() = 0;
@@ -353,11 +357,6 @@ class WebView {
 
   // Custom colors -------------------------------------------------------
 
-  // Sets the default background color when the page has not loaded enough to
-  // know a background colour. This can be overridden by the methods below as
-  // well.
-  virtual void SetBaseBackgroundColor(SkColor) {}
-
   virtual void SetDeviceColorSpaceForTesting(
       const gfx::ColorSpace& color_space) = 0;
 

third_party/blink/renderer/core/exported/web_view_impl.cc

@@ -464,14 +464,16 @@ WebView* WebView::Create(
     CrossVariantMojoAssociatedReceiver<mojom::PageBroadcastInterfaceBase>
         page_handle,
     scheduler::WebAgentGroupScheduler& agent_group_scheduler,
-    const SessionStorageNamespaceId& session_storage_namespace_id) {
+    const SessionStorageNamespaceId& session_storage_namespace_id,
+    absl::optional<SkColor> page_base_background_color) {
   return WebViewImpl::Create(
       client,
       is_hidden ? mojom::blink::PageVisibilityState::kHidden
                 : mojom::blink::PageVisibilityState::kVisible,
       is_inside_portal, compositing_enabled, widgets_never_composited,
       static_cast<WebViewImpl*>(opener), std::move(page_handle),
-      agent_group_scheduler, session_storage_namespace_id);
+      agent_group_scheduler, session_storage_namespace_id,
+      std::move(page_base_background_color));
 }
 
 WebViewImpl* WebViewImpl::Create(
@@ -483,13 +485,15 @@ WebViewImpl* WebViewImpl::Create(
     WebViewImpl* opener,
     mojo::PendingAssociatedReceiver<mojom::blink::PageBroadcast> page_handle,
     blink::scheduler::WebAgentGroupScheduler& agent_group_scheduler,
-    const SessionStorageNamespaceId& session_storage_namespace_id) {
+    const SessionStorageNamespaceId& session_storage_namespace_id,
+    absl::optional<SkColor> page_base_background_color) {
   // Take a self-reference for WebViewImpl that is released by calling Close(),
   // then return a raw pointer to the caller.
   auto web_view = base::AdoptRef(
       new WebViewImpl(client, visibility, is_inside_portal, compositing_enabled,
                       widgets_never_composited, opener, std::move(page_handle),
-                      agent_group_scheduler, session_storage_namespace_id));
+                      agent_group_scheduler, session_storage_namespace_id,
+                      std::move(page_base_background_color)));
   web_view->AddRef();
   return web_view.get();
 }
@@ -553,7 +557,8 @@ WebViewImpl::WebViewImpl(
     WebViewImpl* opener,
     mojo::PendingAssociatedReceiver<mojom::blink::PageBroadcast> page_handle,
     blink::scheduler::WebAgentGroupScheduler& agent_group_scheduler,
-    const SessionStorageNamespaceId& session_storage_namespace_id)
+    const SessionStorageNamespaceId& session_storage_namespace_id,
+    absl::optional<SkColor> page_base_background_color)
     : widgets_never_composited_(widgets_never_composited),
       web_view_client_(client),
       chrome_client_(MakeGarbageCollected<ChromeClientImpl>(this)),
@@ -561,6 +566,8 @@ WebViewImpl::WebViewImpl(
       maximum_zoom_level_(PageZoomFactorToZoomLevel(kMaximumPageZoomFactor)),
       does_composite_(does_composite),
       fullscreen_controller_(std::make_unique<FullscreenController>(this)),
+      page_base_background_color_(
+          page_base_background_color.value_or(SK_ColorWHITE)),
       receiver_(this,
                 std::move(page_handle),
                 agent_group_scheduler.DefaultTaskRunner()),
@@ -3042,14 +3049,17 @@ Color WebViewImpl::BaseBackgroundColor() const {
     return SK_ColorTRANSPARENT;
   if (base_background_color_override_for_inspector_)
     return base_background_color_override_for_inspector_.value();
-  return base_background_color_;
+  // Use the page background color if this is the WebView of the main frame.
+  if (MainFrameImpl())
+    return page_base_background_color_;
+  return Color::kWhite;
 }
 
-void WebViewImpl::SetBaseBackgroundColor(SkColor color) {
-  if (base_background_color_ == color)
+void WebViewImpl::SetPageBaseBackgroundColor(absl::optional<SkColor> color) {
+  SkColor new_color = color.value_or(SK_ColorWHITE);
+  if (page_base_background_color_ == new_color)
     return;
-
-  base_background_color_ = color;
+  page_base_background_color_ = new_color;
   UpdateBaseBackgroundColor();
 }
 

third_party/blink/renderer/core/exported/web_view_impl.h

@@ -120,7 +120,8 @@ class CORE_EXPORT WebViewImpl final : public WebView,
       WebViewImpl* opener,
       mojo::PendingAssociatedReceiver<mojom::blink::PageBroadcast> page_handle,
       scheduler::WebAgentGroupScheduler& agent_group_scheduler,
-      const SessionStorageNamespaceId& session_storage_namespace_id);
+      const SessionStorageNamespaceId& session_storage_namespace_id,
+      absl::optional<SkColor> page_base_background_color);
 
   // All calls to Create() should be balanced with a call to Close(). This
   // synchronously destroys the WebViewImpl.
@@ -198,7 +199,6 @@ class CORE_EXPORT WebViewImpl final : public WebView,
   WebPagePopupImpl* GetPagePopup() const override { return page_popup_.get(); }
   void SetPageFrozen(bool frozen) override;
   WebFrameWidget* MainFrameWidget() override;
-  void SetBaseBackgroundColor(SkColor) override;
   void SetDeviceColorSpaceForTesting(
       const gfx::ColorSpace& color_space) override;
   void PaintContent(cc::PaintCanvas*, const gfx::Rect&) override;
@@ -284,6 +284,7 @@ class CORE_EXPORT WebViewImpl final : public WebView,
       const RendererPreferences& preferences) override;
   void SetHistoryOffsetAndLength(int32_t history_offset,
                                  int32_t history_length) override;
+  void SetPageBaseBackgroundColor(absl::optional<SkColor> color) override;
 
   void DispatchPageshow(base::TimeTicks navigation_start);
   void DispatchPagehide(mojom::blink::PagehideDispatch pagehide_dispatch);
@@ -637,7 +638,8 @@ class CORE_EXPORT WebViewImpl final : public WebView,
       WebViewImpl* opener,
       mojo::PendingAssociatedReceiver<mojom::blink::PageBroadcast> page_handle,
       scheduler::WebAgentGroupScheduler& agent_group_scheduler,
-      const SessionStorageNamespaceId& session_storage_namespace_id);
+      const SessionStorageNamespaceId& session_storage_namespace_id,
+      absl::optional<SkColor> page_base_background_color);
   ~WebViewImpl() override;
 
   void ConfigureAutoResizeMode();
@@ -825,7 +827,7 @@ class CORE_EXPORT WebViewImpl final : public WebView,
   absl::optional<SkColor> background_color_override_for_fullscreen_controller_;
   bool override_base_background_color_to_transparent_ = false;
   absl::optional<SkColor> base_background_color_override_for_inspector_;
-  SkColor base_background_color_ = Color::kWhite;
+  SkColor page_base_background_color_;  // Only applies to main frame.
 
   float zoom_factor_override_ = 0.f;
 

third_party/blink/renderer/core/exported/web_view_test.cc

@@ -433,7 +433,7 @@ TEST_F(WebViewTest, SetBaseBackgroundColor) {
   WebViewImpl* web_view = web_view_helper_.Initialize();
   EXPECT_EQ(SK_ColorWHITE, web_view->BackgroundColor());
 
-  web_view->SetBaseBackgroundColor(SK_ColorBLUE);
+  web_view->SetPageBaseBackgroundColor(SK_ColorBLUE);
   EXPECT_EQ(SK_ColorBLUE, web_view->BackgroundColor());
 
   WebURL base_url = url_test_helpers::ToKURL("http://example.com/");
@@ -453,11 +453,11 @@ TEST_F(WebViewTest, SetBaseBackgroundColor) {
   // Expected: red (50% alpha) blended atop base of SK_ColorBLUE.
   EXPECT_EQ(0xFF80007F, web_view->BackgroundColor());
 
-  web_view->SetBaseBackgroundColor(kTranslucentPutty);
+  web_view->SetPageBaseBackgroundColor(kTranslucentPutty);
   // Expected: red (50% alpha) blended atop kTranslucentPutty. Note the alpha.
   EXPECT_EQ(0xBFE93A31, web_view->BackgroundColor());
 
-  web_view->SetBaseBackgroundColor(SK_ColorTRANSPARENT);
+  web_view->SetPageBaseBackgroundColor(SK_ColorTRANSPARENT);
   frame_test_helpers::LoadHTMLString(web_view->MainFrameImpl(),
                                      "<html><head><style>body "
                                      "{background-color:transparent}</style></"
@@ -494,13 +494,15 @@ TEST_F(WebViewTest, SetBaseBackgroundColorBeforeMainFrame) {
                       /*widgets_never_composited=*/false,
                       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),
                       web_view_helper_.GetAgentGroupScheduler(),
-                      /*session_storage_namespace_id=*/base::EmptyString()));
+                      /*session_storage_namespace_id=*/base::EmptyString(),
+                      /*page_base_background_color=*/absl::nullopt));
 
   EXPECT_NE(SK_ColorBLUE, web_view->BackgroundColor());
-  // WebView does not have a frame yet, but we should still be able to set the
-  // background color.
-  web_view->SetBaseBackgroundColor(SK_ColorBLUE);
-  EXPECT_EQ(SK_ColorBLUE, web_view->BackgroundColor());
+  // WebView does not have a frame yet; while it's possible to set the page
+  // background color, it won't have any effect until a local main frame is
+  // attached.
+  web_view->SetPageBaseBackgroundColor(SK_ColorBLUE);
+  EXPECT_NE(SK_ColorBLUE, web_view->BackgroundColor());
 
   frame_test_helpers::TestWebFrameClient web_frame_client;
   WebLocalFrame* frame = WebLocalFrame::CreateMainFrame(
@@ -528,7 +530,7 @@ TEST_F(WebViewTest, SetBaseBackgroundColorAndBlendWithExistingContent) {
   WebViewImpl* web_view = web_view_helper_.Initialize();
 
   // Set WebView background to green with alpha.
-  web_view->SetBaseBackgroundColor(kAlphaGreen);
+  web_view->SetPageBaseBackgroundColor(kAlphaGreen);
   web_view->GetSettings()->SetShouldClearDocumentBackground(false);
   web_view->MainFrameViewWidget()->Resize(gfx::Size(kWidth, kHeight));
   UpdateAllLifecyclePhases();
@@ -569,7 +571,7 @@ TEST_F(WebViewTest, SetBaseBackgroundColorWithColorScheme) {
   ColorSchemeHelper color_scheme_helper(*(web_view->GetPage()));
   color_scheme_helper.SetPreferredColorScheme(
       mojom::blink::PreferredColorScheme::kLight);
-  web_view->SetBaseBackgroundColor(SK_ColorBLUE);
+  web_view->SetPageBaseBackgroundColor(SK_ColorBLUE);
 
   WebURL base_url = url_test_helpers::ToKURL("http://example.com/");
   frame_test_helpers::LoadHTMLString(
@@ -586,9 +588,9 @@ TEST_F(WebViewTest, SetBaseBackgroundColorWithColorScheme) {
   EXPECT_EQ(Color(0x12, 0x12, 0x12), frame_view->BaseBackgroundColor());
 
   // Don't let dark color-scheme override a transparent background.
-  web_view->SetBaseBackgroundColor(SK_ColorTRANSPARENT);
+  web_view->SetPageBaseBackgroundColor(SK_ColorTRANSPARENT);
   EXPECT_EQ(Color::kTransparent, frame_view->BaseBackgroundColor());
-  web_view->SetBaseBackgroundColor(SK_ColorBLUE);
+  web_view->SetPageBaseBackgroundColor(SK_ColorBLUE);
   EXPECT_EQ(Color(0x12, 0x12, 0x12), frame_view->BaseBackgroundColor());
 
   color_scheme_helper.SetForcedColors(*(web_view->GetPage()),
@@ -2740,7 +2742,8 @@ TEST_F(WebViewTest, ClientTapHandlingNullWebViewClient) {
       /*widgets_never_composited=*/false,
       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),
       web_view_helper_.GetAgentGroupScheduler(),
-      /*session_storage_namespace_id=*/base::EmptyString()));
+      /*session_storage_namespace_id=*/base::EmptyString(),
+      /*page_base_background_color=*/absl::nullopt));
   frame_test_helpers::TestWebFrameClient web_frame_client;
   WebLocalFrame* local_frame = WebLocalFrame::CreateMainFrame(
       web_view, &web_frame_client, nullptr, LocalFrameToken(), nullptr);

third_party/blink/renderer/core/frame/frame_test_helpers.cc

@@ -620,7 +620,8 @@ void WebViewHelper::InitializeWebView(TestWebViewClient* web_view_client,
                       /*widgets_never_composited=*/false,
                       /*opener=*/opener, mojo::NullAssociatedReceiver(),
                       *agent_group_scheduler_,
-                      /*session_storage_namespace_id=*/base::EmptyString()));
+                      /*session_storage_namespace_id=*/base::EmptyString(),
+                      /*page_base_background_color=*/absl::nullopt));
   // This property must be set at initialization time, it is not supported to be
   // changed afterward, and does nothing.
   web_view_->GetSettings()->SetViewportEnabled(viewport_enabled_);

third_party/blink/renderer/core/layout/scrollbars_test.cc

@@ -449,7 +449,7 @@ TEST_P(ScrollbarsTest, TransparentBackgroundUsesDarkOverlayColorTheme) {
   ENABLE_OVERLAY_SCROLLBARS(true);
 
   WebView().MainFrameViewWidget()->Resize(gfx::Size(800, 600));
-  WebView().SetBaseBackgroundColor(SK_ColorTRANSPARENT);
+  WebView().SetPageBaseBackgroundColor(SK_ColorTRANSPARENT);
   SimRequest request("https://example.com/test.html", "text/html");
   LoadURL("https://example.com/test.html");
   request.Complete(R"HTML(

third_party/blink/renderer/core/page/autoscroll_controller_test.cc

@@ -26,7 +26,7 @@ class AutoscrollControllerTest : public SimTest {
 TEST_F(AutoscrollControllerTest,
        CrashWhenLayoutStopAnimationBeforeScheduleAnimation) {
   WebView().MainFrameViewWidget()->Resize(gfx::Size(800, 600));
-  WebView().SetBaseBackgroundColor(SK_ColorTRANSPARENT);
+  WebView().SetPageBaseBackgroundColor(SK_ColorTRANSPARENT);
   SimRequest request("https://example.com/test.html", "text/html");
   LoadURL("https://example.com/test.html");
   request.Complete(R"HTML(

third_party/blink/renderer/modules/peerconnection/webrtc_audio_renderer_test.cc

@@ -148,7 +148,8 @@ class MAYBE_WebRtcAudioRendererTest : public testing::Test {
             /*opener=*/nullptr,
             mojo::NullAssociatedReceiver(),
             *agent_group_scheduler_,
-            /*session_storage_namespace_id=*/base::EmptyString())),
+            /*session_storage_namespace_id=*/base::EmptyString(),
+            /*page_base_background_color=*/absl::nullopt)),
         web_local_frame_(
             blink::WebLocalFrame::CreateMainFrame(web_view_,
                                                   &web_local_frame_client_,

weblayer/browser/content_view_render_view.cc

@@ -24,6 +24,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
+#include "third_party/abseil-cpp/absl/types/optional.h"
 #include "ui/android/resources/resource_manager.h"
 #include "ui/android/view_android.h"
 #include "ui/android/window_android.h"
@@ -36,67 +37,6 @@ using base::android::ScopedJavaLocalRef;
 
 namespace weblayer {
 
-namespace {
-
-// Setting the page's various background color is convoluted and brittle and
-// buggy. This is code inspired from chromeos views and should be considered
-// temporary until content API can be fixed to be more robust. This is
-// effectively only passing 1 bit of information, whether the background color
-// is fully transparent or not, as the actual color isn't used by anything.
-class WebContentsSetBackgroundColor
-    : public content::WebContentsObserver,
-      public content::WebContentsUserData<WebContentsSetBackgroundColor> {
- public:
-  static void Set(content::WebContents* web_contents,
-                  SkColor background_color) {
-    if (auto* set = FromWebContents(web_contents)) {
-      set->SetBackgroundColor(background_color);
-      return;
-    }
-
-    // SupportsUserData::Data takes ownership over the
-    // WebContentsSetBackgroundColor instance and will destroy it when the
-    // WebContents instance is destroyed.
-    web_contents->SetUserData(
-        UserDataKey(), base::WrapUnique(new WebContentsSetBackgroundColor(
-                           web_contents, background_color)));
-  }
-
-  ~WebContentsSetBackgroundColor() override = default;
-
- private:
-  friend class content::WebContentsUserData<WebContentsSetBackgroundColor>;
-  WebContentsSetBackgroundColor(content::WebContents* web_contents,
-                                SkColor color)
-      : content::WebContentsObserver(web_contents), color_(color) {}
-
-  // content::WebContentsObserver:
-  void RenderViewHostChanged(content::RenderViewHost* old_host,
-                             content::RenderViewHost* new_host) override {
-    new_host->GetWidget()->GetView()->SetBackgroundColor(color_);
-  }
-
-  void SetBackgroundColor(SkColor background_color) {
-    if (color_ == background_color)
-      return;
-
-    color_ = background_color;
-    web_contents()
-        ->GetRenderViewHost()
-        ->GetWidget()
-        ->GetView()
-        ->SetBackgroundColor(color_);
-  }
-
-  SkColor color_;
-
-  WEB_CONTENTS_USER_DATA_KEY_DECL();
-};
-
-WEB_CONTENTS_USER_DATA_KEY_IMPL(WebContentsSetBackgroundColor)
-
-}  // namespace
-
 ContentViewRenderView::ContentViewRenderView(JNIEnv* env,
                                              jobject obj,
                                              gfx::NativeWindow root_window)
@@ -136,11 +76,8 @@ void ContentViewRenderView::SetCurrentWebContents(
   InitCompositor();
   content::WebContents* web_contents =
       content::WebContents::FromJavaWebContents(jweb_contents);
-  if (web_contents_) {
-    WebContentsSetBackgroundColor::Set(
-        web_contents_,
-        Java_ContentViewRenderView_getBackgroundColor(env, java_obj_));
-  }
+  if (web_contents_)
+    web_contents_->SetPageBaseBackgroundColor(absl::nullopt);
   if (web_contents_layer_)
     web_contents_layer_->RemoveFromParent();
 
@@ -271,12 +208,9 @@ void ContentViewRenderView::InitCompositor() {
 void ContentViewRenderView::UpdateWebContentsBaseBackgroundColor() {
   if (!web_contents_)
     return;
-  JNIEnv* env = base::android::AttachCurrentThread();
-  WebContentsSetBackgroundColor::Set(
-      web_contents_,
-      use_transparent_background_
-          ? SK_ColorTRANSPARENT
-          : Java_ContentViewRenderView_getBackgroundColor(env, java_obj_));
+  web_contents_->SetPageBaseBackgroundColor(
+      use_transparent_background_ ? absl::make_optional(SK_ColorTRANSPARENT)
+                                  : absl::nullopt);
 }
 
 }  // namespace weblayer