[content] Fix background color update handling in RWHVAura.

content/browser/frame_host/render_widget_host_view_child_frame.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_CHILD_FRAME_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_CHILD_FRAME_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 67 matching lines @@
   bool IsSurfaceAvailableForCopy() const override;
   void Show() override;
   void Hide() override;
   bool IsShowing() override;
   gfx::Rect GetViewBounds() const override;
   gfx::Size GetVisibleViewportSize() const override;
   gfx::Vector2dF GetLastScrollOffset() const override;
   gfx::NativeView GetNativeView() const override;
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
   void SetBackgroundColor(SkColor color) override;
+  SkColor background_color() const override;
   gfx::Size GetPhysicalBackingSize() const override;
   bool IsMouseLocked() override;
   void SetNeedsBeginFrames(bool needs_begin_frames) override;
 
   // RenderWidgetHostViewBase implementation.
   void InitAsPopup(RenderWidgetHostView* parent_host_view,
                    const gfx::Rect& bounds) override;
   void InitAsFullscreen(RenderWidgetHostView* reference_host_view) override;
   void UpdateCursor(const WebCursor& cursor) override;
   void SetIsLoading(bool is_loading) override;
@@ skipping 151 matching lines @@
   void ResetCompositorFrameSinkSupport();
 
   using FrameSwappedCallbackList = std::deque<std::unique_ptr<base::Closure>>;
   // Since frame-drawn callbacks are "fire once", we use std::deque to make
   // it convenient to swap() when processing the list.
   FrameSwappedCallbackList frame_swapped_callbacks_;
 
   // The surface client ID of the parent RenderWidgetHostView.  0 if none.
   cc::FrameSinkId parent_frame_sink_id_;
 
+  // The background color of the widget.
+  SkColor background_color_;
+
   base::WeakPtrFactory<RenderWidgetHostViewChildFrame> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewChildFrame);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_CHILD_FRAME_H_