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

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index d65865f1daa8c63a8be4e37643f5975b0f7411d3..ce9f106e689cee39d2bf95a67c7e4de291e52460 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -307,11 +307,6 @@ class CONTENT_EXPORT RenderWidget
   void DoDeferredClose();
   void DoDeferredSetWindowRect(const blink::WebRect& pos);
 
-  // Set the background of the render widget to a bitmap. The bitmap will be
-  // tiled in both directions if it isn't big enough to fill the area. This is
-  // mainly intended to be used in conjuction with WebView::SetIsTransparent().
-  virtual void SetBackground(const SkBitmap& bitmap);
-
   // Resizes the render widget.
   void Resize(const gfx::Size& new_size,
               const gfx::Size& physical_backing_size,
@@ -633,9 +628,6 @@ class CONTENT_EXPORT RenderWidget
   typedef std::vector<WebPluginGeometry> WebPluginGeometryVector;
   WebPluginGeometryVector plugin_window_moves_;
 
-  // A custom background for the widget.
-  SkBitmap background_;
-
   // While we are waiting for the browser to update window sizes, we track the
   // pending size temporarily.
   int pending_window_rect_count_;