[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 543ca061fbe800fd4cf91d37df3134bc9729d759..4c613be4360bc0682316cff4a83de06742972477 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -112,6 +112,7 @@ 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;
@@ -463,6 +464,10 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   // Tells DelegatedFrameHost whether we need to receive BeginFrames.
   void UpdateNeedsBeginFramesInternal();
 
+  // Applies background color without notifying the RenderWidget about
+  // opaqueness changes.
+  void UpdateBackgroundColorFromRenderer(SkColor color);
+
   // The model object.
   RenderWidgetHostImpl* const host_;
 
@@ -507,6 +512,9 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   // Current tooltip text.
   base::string16 tooltip_;
 
+  // The background color of the web content.
+  SkColor background_color_;
+
   // Whether a request for begin frames has been issued.
   bool needs_begin_frames_;