RenderWidget's scheduleComposite should return a bool. (true iff a prompt composite will come).

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 00ea03cf28d0ea332a6dcc6eaa7f1169d14527c2..d564c06e8ed6a1d5d8a14576e1b4b68ca84b22e4 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -122,7 +122,11 @@ class CONTENT_EXPORT RenderWidget
   virtual void didBecomeReadyForAdditionalInput();
   virtual void didCommitAndDrawCompositorFrame();
   virtual void didCompleteSwapBuffers();
+#if defined(WEBWIDGETCLIENT_SCHEDULECOMPOSITE_RETURNS_BOOL)
+  virtual bool scheduleComposite();
+#else
   virtual void scheduleComposite();
+#endif
   virtual void scheduleAnimation();
   virtual void didFocus();
   virtual void didBlur();
@@ -207,6 +211,12 @@ class CONTENT_EXPORT RenderWidget
   void DoDeferredClose();
   void DoDeferredSetWindowRect(const WebKit::WebRect& pos);
 
+  // Returns true if a deferred update is possible.
+  bool CanDoDeferredUpdate() const;
+
+  // Returns true if a deferred update should be suppressed, even if possible.
+  bool ShouldSuppressDeferredUpdates() const;
+
   // 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().