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

content/browser/renderer_host/render_widget_host_impl.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_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 
 #include <deque>
 #include <list>
 #include <map>
@@ skipping 366 matching lines @@
 
   // Event queries delegated to the |input_router_|.
   bool ShouldForwardTouchEvent() const;
 
   bool has_touch_handler() const { return has_touch_handler_; }
 
   // Notification that the user has made some kind of input that could
   // perform an action. See OnUserGesture for more details.
   void StartUserGesture();
 
-  // Set the RenderView background.
-  void SetBackground(const SkBitmap& background);
+  // Set the RenderView background transparency.
+  void SetBackgroundOpaque(bool opaque);
 
   // Notifies the renderer that the next key event is bound to one or more
   // pre-defined edit commands
   void SetEditCommandsForNextKeyEvent(
       const std::vector<EditCommand>& commands);
 
   // Gets the accessibility mode.
   AccessibilityMode accessibility_mode() const {
     return accessibility_mode_;
   }
@@ skipping 486 matching lines @@
 #endif
 
   int64 last_input_number_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_