Protoype Mac input event filter

content/browser/renderer_host/render_widget_host_view_mac.h

Index: content/browser/renderer_host/render_widget_host_view_mac.h
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.h b/content/browser/renderer_host/render_widget_host_view_mac.h
index 3f3fc1e44f25f547749458a1b32cf99a58087924..d4a794a091b6a678db7923c8343caf8ea7f68a42 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -35,9 +35,11 @@
 #include "ui/gfx/display_observer.h"
 
 namespace content {
+class RenderWidgetHostImpl;
 class RenderWidgetHostViewMac;
 class RenderWidgetHostViewMacEditCommandHelper;
 class WebContents;
+class WheelEventRailFilterMac;
 }
 
 namespace ui {
@@ -199,7 +201,6 @@ class Layer;
 @end
 
 namespace content {
-class RenderWidgetHostImpl;
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewMac
@@ -237,6 +238,8 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
 
   RenderWidgetHostViewCocoa* cocoa_view() const { return cocoa_view_; }
 
+  scoped_ptr<WheelEventRailFilterMac> wheel_event_rail_filter_;
+
   // |delegate| is used to separate out the logic from the NSResponder delegate.
   // |delegate| is retained by this class.
   // |delegate| should be set at most once.