Remove RenderWidget::SetBackground, change IPC to pass a bool.

content/browser/renderer_host/render_widget_host_view_mac.h

 // Copyright (c) 2012 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_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <list>
 #include <map>
@@ skipping 239 matching lines @@
   virtual void SetShowingContextMenu(bool showing) OVERRIDE;
   virtual void SetActive(bool active) OVERRIDE;
   virtual void SetTakesFocusOnlyOnMouseDown(bool flag) OVERRIDE;
   virtual void SetWindowVisibility(bool visible) OVERRIDE;
   virtual void WindowFrameChanged() OVERRIDE;
   virtual void ShowDefinitionForSelection() OVERRIDE;
   virtual bool SupportsSpeech() const OVERRIDE;
   virtual void SpeakSelection() OVERRIDE;
   virtual bool IsSpeaking() const OVERRIDE;
   virtual void StopSpeaking() OVERRIDE;
-  virtual void SetBackground(const SkBitmap& background) OVERRIDE;
+  virtual void SetBackgroundOpaque(bool opaque) OVERRIDE;
 
   // Implementation of RenderWidgetHostViewBase.
   virtual void InitAsPopup(RenderWidgetHostView* parent_host_view,
                            const gfx::Rect& pos) OVERRIDE;
   virtual void InitAsFullscreen(
       RenderWidgetHostView* reference_host_view) OVERRIDE;
   virtual void WasShown() OVERRIDE;
   virtual void WasHidden() OVERRIDE;
   virtual void MovePluginWindows(
       const std::vector<WebPluginGeometry>& moves) OVERRIDE;
@@ skipping 372 matching lines @@
   scoped_ptr<RenderWidgetHostViewFrameSubscriber> frame_subscriber_;
 
   base::WeakPtrFactory<RenderWidgetHostViewMac>
       software_frame_weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_