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

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

Index: third_party/WebKit/Source/core/events/TouchEvent.h
diff --git a/third_party/WebKit/Source/core/events/TouchEvent.h b/third_party/WebKit/Source/core/events/TouchEvent.h
index 4bb598dc6c385cf614f029f82e7e3d20ac94974e..aa4d5a1c2fb7d6aff2aedb60f6b70c0e101b8a01 100644
--- a/third_party/WebKit/Source/core/events/TouchEvent.h
+++ b/third_party/WebKit/Source/core/events/TouchEvent.h
@@ -48,11 +48,14 @@ public:
     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)
@@ -76,6 +79,7 @@ public:
 
     bool causesScrollingIfUncanceled() const { return m_causesScrollingIfUncanceled; }
 
+    bool firstTouchMoveAfterTouchStart() const { return m_firstTouchMoveAfterTouchStart; }
     bool isTouchEvent() const override;
 
     const AtomicString& interfaceName() const override;
@@ -92,13 +96,14 @@ private:
         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 {