Revert of Remove default args to several PageWidgetDelegate members.

Source/web/PageWidgetDelegate.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 54 matching lines @@
 // Common implementation of WebViewImpl and WebPagePopupImpl.
 class PageWidgetDelegate {
 public:
     enum CanvasBackground {
         Opaque,
         Translucent,
     };
     // rootFrame arguments indicate a root localFrame from which to start performing the
     // specified operation. If rootFrame is 0, these methods will attempt to use the
     // Page's mainFrame(), if it is a LocalFrame.
-    static void animate(Page*, double monotonicFrameBeginTime, LocalFrame* root);
-    static void layout(Page*, LocalFrame* root);
-    static void paint(Page*, PageOverlayList*, WebCanvas*, const WebRect&, CanvasBackground, LocalFrame* root);
-    static bool handleInputEvent(Page*, PageWidgetEventHandler&, const WebInputEvent&, LocalFrame* root);
+    static void animate(Page*, double monotonicFrameBeginTime, LocalFrame* rootFrame = 0);
+    static void layout(Page*, LocalFrame* rootFrame = 0);
+    static void paint(Page*, PageOverlayList*, WebCanvas*, const WebRect&, CanvasBackground, LocalFrame* rootFrame = 0);
+    static bool handleInputEvent(Page*, PageWidgetEventHandler&, const WebInputEvent&, LocalFrame* rootFrame = 0);
 
 private:
     PageWidgetDelegate() { }
 };
 
 }
 #endif