Filter unnecessary GestureFlingCancel events.

content/browser/renderer_host/render_widget_host_impl.h

Index: content/browser/renderer_host/render_widget_host_impl.h
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index b7a528e2104f2a476d8331b6cda2eaa63825b938..2e907b054950f856767cde2f657c523bc9cf27a4 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -600,6 +600,11 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   // initiated by OnMsgBeginSmoothScroll.
   void TickActiveSmoothScrollGesture();
 
+  // Returns |true| if the given GestureFlingCancel should be discarded
+  // as unnecessary.
+  bool ShouldDiscardFlingCancelEvent(
+      const WebKit::WebGestureEvent& gesture_event);
+
   // Our delegate, which wants to know mainly about keyboard events.
   RenderWidgetHostDelegate* delegate_;
 
@@ -777,6 +782,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
 
   scoped_ptr<TapSuppressionController> tap_suppression_controller_;
 
+  bool fling_in_progress_;
+
   scoped_ptr<SmoothScrollGesture> active_smooth_scroll_gesture_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);