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

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 18c97d714d46984115f23caae9d89131293c352a..c67df8b6c5f237fef4e76d90b572f1aa37a8298f 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -1669,13 +1669,6 @@ void RenderWidget::DidToggleFullscreen() {
   }
 }
 
-void RenderWidget::SetBackground(const SkBitmap& background) {
-  background_ = background;
-
-  // Generate a full repaint.
-  didInvalidateRect(gfx::Rect(size_.width(), size_.height()));
-}
-
 bool RenderWidget::next_paint_is_resize_ack() const {
   return ViewHostMsg_UpdateRect_Flags::is_resize_ack(next_paint_flags_);
 }