Query the preferred readback config in CopyFromBackingStore

content/browser/renderer_host/render_widget_host_impl.h

Index: content/browser/renderer_host/render_widget_host_impl.h
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index aa8951841c76f18066844a2f62b2f74654f75829..f6db1399a145d94cb9cfae7498e0e30395f625bf 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -136,7 +136,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   virtual void CopyFromBackingStore(
       const gfx::Rect& src_rect,
       const gfx::Size& accelerated_dst_size,
-      const base::Callback<void(bool, const SkBitmap&)>& callback) OVERRIDE;
+      const base::Callback<void(bool, const SkBitmap&)>& callback,
+      const SkBitmap::Config& bitmap_config) OVERRIDE;
 #if defined(TOOLKIT_GTK)
   virtual bool CopyFromBackingStoreToGtkWindow(const gfx::Rect& dest_rect,
                                                GdkWindow* target) OVERRIDE;
@@ -178,6 +179,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
       const gfx::Rect& src_subrect,
       const base::Callback<void(bool, const SkBitmap&)>& callback) OVERRIDE;
 
+  virtual SkBitmap::Config PreferredReadbackFormat() OVERRIDE;
+
   const NativeWebKeyboardEvent* GetLastKeyboardEvent() const;
 
   // Notification that the screen info has changed.