[content] Fix background color update handling in RWHVAura.

content/browser/renderer_host/render_widget_host_view_android.h

Index: content/browser/renderer_host/render_widget_host_view_android.h
diff --git a/content/browser/renderer_host/render_widget_host_view_android.h b/content/browser/renderer_host/render_widget_host_view_android.h
index a1492ec2b37ec8fcb379fc592c750eafc748c138..0c4a507e5408d06fad84a954ccb0417eb71ab69c 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.h
+++ b/content/browser/renderer_host/render_widget_host_view_android.h
@@ -118,6 +118,7 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
   void SetTooltipText(const base::string16& tooltip_text) override;
   bool HasAcceleratedSurface(const gfx::Size& desired_size) override;
   void SetBackgroundColor(SkColor color) override;
+  SkColor background_color() const override;
   gfx::Rect GetBoundsInRootWindow() override;
   void ProcessAckedTouchEvent(const TouchEventWithLatencyInfo& touch,
                               InputEventAckState ack_result) override;
@@ -352,6 +353,9 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
 
   ImeAdapterAndroid* ime_adapter_android_;
 
+  // The background color of the widget.
+  SkColor background_color_;
+
   // Body background color of the underlying document.
   SkColor cached_background_color_;