Add UMA metric for tracking root level listeners for blocking touch.

third_party/WebKit/Source/core/events/TouchEvent.h

 /*
  * Copyright 2008, The Android Open Source Project
  * Copyright (C) 2012 Research In Motion Limited. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
@@ skipping 30 matching lines @@
     ~TouchEvent() override;
 
     // We only initialize sourceCapabilities when we create TouchEvent from EventHandler, null if it is from JavaScript.
     static TouchEvent* create()
     {
         return new TouchEvent;
     }
     static TouchEvent* create(TouchList* touches,
         TouchList* targetTouches, TouchList* changedTouches,
         const AtomicString& type, AbstractView* view,
-        PlatformEvent::Modifiers modifiers, bool cancelable, bool causesScrollingIfUncanceled,
+        PlatformEvent::Modifiers modifiers, bool cancelable,
+        bool causesScrollingIfUncanceled, bool firstTouchMoveAfterTouchStart,

[tdresser, 2016/04/07 12:22:08]

firstTouchMoveAfterScrollStart is a bit confusing, because it's actually the
first touchmove than isn't filtered out by the slop region.

Maybe touchMoveStartingScroll or firstTouchMoveAfterSlopRegion?

[dtapuska, 2016/04/19 17:54:47]

Removed

         double platformTimeStamp)
     {
-        return new TouchEvent(touches, targetTouches, changedTouches, type, view,
-            modifiers, cancelable, causesScrollingIfUncanceled, platformTimeStamp);
+        return new TouchEvent(touches, targetTouches, changedTouches,
+            type, view, modifiers, cancelable,
+            causesScrollingIfUncanceled,
+            firstTouchMoveAfterTouchStart, platformTimeStamp);
     }
 
     static TouchEvent* create(const AtomicString& type, const TouchEventInit& initializer)
     {
         return new TouchEvent(type, initializer);
     }
 
     void initTouchEvent(ScriptState*, TouchList* touches, TouchList* targetTouches,
         TouchList* changedTouches, const AtomicString& type,
         AbstractView*,
         int, int, int, int, // unused useless members of web exposed API
         bool ctrlKey, bool altKey, bool shiftKey, bool metaKey);
 
     TouchList* touches() const { return m_touches.get(); }
     TouchList* targetTouches() const { return m_targetTouches.get(); }
     TouchList* changedTouches() const { return m_changedTouches.get(); }
 
     void setTouches(TouchList* touches) { m_touches = touches; }
     void setTargetTouches(TouchList* targetTouches) { m_targetTouches = targetTouches; }
     void setChangedTouches(TouchList* changedTouches) { m_changedTouches = changedTouches; }
 
     bool causesScrollingIfUncanceled() const { return m_causesScrollingIfUncanceled; }
 
+    bool firstTouchMoveAfterTouchStart() const { return m_firstTouchMoveAfterTouchStart; }
     bool isTouchEvent() const override;
 
     const AtomicString& interfaceName() const override;
 
     void preventDefault() override;
 
     EventDispatchMediator* createMediator() override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     TouchEvent();
     TouchEvent(TouchList* touches, TouchList* targetTouches,
         TouchList* changedTouches, const AtomicString& type,
         AbstractView*, PlatformEvent::Modifiers,
         bool cancelable, bool causesScrollingIfUncanceled,
-        double platformTimeStamp);
+        bool firstTouchMoveAfterTouchStart, double platformTimeStamp);
     TouchEvent(const AtomicString&, const TouchEventInit&);
 
     Member<TouchList> m_touches;
     Member<TouchList> m_targetTouches;
     Member<TouchList> m_changedTouches;
     bool m_causesScrollingIfUncanceled;
+    bool m_firstTouchMoveAfterTouchStart;
 };
 
 class TouchEventDispatchMediator final : public EventDispatchMediator {
 public:
     static TouchEventDispatchMediator* create(TouchEvent*);
 
 private:
     explicit TouchEventDispatchMediator(TouchEvent*);
     TouchEvent& event() const;
     DispatchEventResult dispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(TouchEvent);
 
 } // namespace blink
 
 #endif // TouchEvent_h