[Mac] Rubber-banding on Lion.

content/browser/renderer_host/render_widget_host.h

Index: content/browser/renderer_host/render_widget_host.h
===================================================================
--- content/browser/renderer_host/render_widget_host.h	(revision 96200)
+++ content/browser/renderer_host/render_widget_host.h	(working copy)
@@ -260,6 +260,7 @@
   // Called when a mouse click activates the renderer.
   virtual void OnMouseActivate();
   void ForwardWheelEvent(const WebKit::WebMouseWheelEvent& wheel_event);
+  void ForwardGestureEvent(const WebKit::WebGestureEvent& gesture_event);
   virtual void ForwardKeyboardEvent(const NativeWebKeyboardEvent& key_event);
   virtual void ForwardTouchEvent(const WebKit::WebTouchEvent& touch_event);
 
@@ -366,6 +367,7 @@
   void ActivateDeferredPluginHandles();
 
   const gfx::Point& last_scroll_offset() const { return last_scroll_offset_; }
+  const gfx::Size& contents_size() const { return contents_size_; }
 
   // Notification that the user has made some kind of input that could
   // perform an action. See OnUserGesture for more details.
@@ -550,6 +552,13 @@
   // The current size of the RenderWidget.
   gfx::Size current_size_;
 
+  // The size of the underlying contents, including parts that are not visible
+  // due to scrolling. It can be used to calculate the view port bounds using
+  // |last_scroll_offset_|. Note: This size is not always available. In
+  // particular, it is only available for RenderViews after a paint has taken
+  // place. Additionally, it only available on the Mac.
+  gfx::Size contents_size_;
+
   // The current reserved area of the RenderWidget where contents should not be
   // rendered to draw the resize corner, sidebar mini tabs etc.
   gfx::Rect current_reserved_rect_;