Allow touch events to be uncancelable

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 12 matching lines @@
 #include "platform/PlatformEvent.h"
 #include "platform/PlatformTouchPoint.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class PlatformTouchEvent : public PlatformEvent {
 public:
     PlatformTouchEvent()
         : PlatformEvent(PlatformEvent::TouchStart)
+        , m_cancelable(true)
     {
     }
 
     const Vector<PlatformTouchPoint>& touchPoints() const { return m_touchPoints; }
 
+    bool cancelable() const { return m_cancelable; }
+
 protected:
     Vector<PlatformTouchPoint> m_touchPoints;
+    bool m_cancelable;
 };
 
 }
 
 #endif // PlatformTouchEvent_h