[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 95990)
+++ 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 +552,11 @@
   // 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_|.

[brettw, 2011/08/11 00:08:27]

We should make it clear that this isn't always available, and do our best to
explain when it is.

It's my understanding that this is only available on Mac. If this is correct, we
should mention that, and also that it's only available for RenderViews and may
be 0 if there hasn't been a paint yet (or something like that).

+  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_;