[content] Fix background color update handling in RWHVAura.

content/browser/renderer_host/render_widget_host_view_aura.h

Index: content/browser/renderer_host/render_widget_host_view_aura.h
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.h b/content/browser/renderer_host/render_widget_host_view_aura.h
index dabb04812ca2bc06b00a9089d49b27dace889d67..bb9ec402da30db06506fcccfbdb304057551497f 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -115,6 +115,7 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   bool IsShowing() override;
   gfx::Rect GetViewBounds() const override;
   void SetBackgroundColor(SkColor color) override;
+  SkColor background_color() const override;
   bool IsMouseLocked() override;
   gfx::Size GetVisibleViewportSize() const override;
   void SetInsets(const gfx::Insets& insets) override;
@@ -465,6 +466,10 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   // Adds/Removes frame observer based on state.
   void UpdateNeedsBeginFramesInternal();
 
+  // Applies background color without notifying the RenderWidget about
+  // opaqueness changes.
+  void UpdateBackgroundColorFromRenderer(SkColor color);
+
   // The model object.
   RenderWidgetHostImpl* const host_;
 
@@ -509,6 +514,9 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   // Current tooltip text.
   base::string16 tooltip_;
 
+  // The background color of the web content.
+  SkColor background_color_;
+
   // The begin frame source being observed.  Null if none.
   cc::BeginFrameSource* begin_frame_source_;
   cc::BeginFrameArgs last_begin_frame_args_;