Add UMA metric for tracking listeners for blocking touch while fling is happening

third_party/WebKit/Source/platform/PlatformTouchEvent.h

 /*
     Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies)
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 14 matching lines @@
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class PlatformTouchEvent : public PlatformEvent {
 public:
     PlatformTouchEvent()
         : PlatformEvent(PlatformEvent::TouchStart)
         , m_dispatchType(PlatformEvent::Blocking)
         , m_causesScrollingIfUncanceled(false)
+        , m_dispatchedDuringFling(false)
     {
     }
 
     const Vector<PlatformTouchPoint>& touchPoints() const { return m_touchPoints; }
 
     DispatchType dispatchType() const { return m_dispatchType; }
     bool cancelable() const { return m_dispatchType == PlatformEvent::Blocking; }
     bool causesScrollingIfUncanceled() const { return m_causesScrollingIfUncanceled; }
+    bool dispatchedDuringFling() const { return m_dispatchedDuringFling; }
 
 protected:
     Vector<PlatformTouchPoint> m_touchPoints;
     DispatchType m_dispatchType;
     bool m_causesScrollingIfUncanceled;
+    bool m_dispatchedDuringFling;
 };
 
 } // namespace blink
 
 #endif // PlatformTouchEvent_h