Make first TouchStart and first TouchMove events on a flinging layer non-blocking

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

Index: third_party/WebKit/Source/core/events/Event.h
diff --git a/third_party/WebKit/Source/core/events/Event.h b/third_party/WebKit/Source/core/events/Event.h
index 7becfcd5374edd35a3eef066830037b2a10e79e7..686d0a94768d1c9bbaee3e62dc4ddb3a02783177 100644
--- a/third_party/WebKit/Source/core/events/Event.h
+++ b/third_party/WebKit/Source/core/events/Event.h
@@ -215,6 +215,8 @@ public:
 
     bool preventDefaultCalledDuringPassive() const { return m_preventDefaultCalledDuringPassive; }
 
+    bool preventDefaultCalledOnUncancelableEvent() const { return m_preventDefaultCalledOnUncancelableEvent; }
+
     DECLARE_VIRTUAL_TRACE();
 
 protected:
@@ -255,6 +257,8 @@ private:
     // Whether preventDefault was called when |m_handlingPassive| is
     // true. This field is reset on each call to setHandlingPassive.
     unsigned m_preventDefaultCalledDuringPassive : 1;
+    // Whether preventDefault was called on uncancelable event.
+    unsigned m_preventDefaultCalledOnUncancelableEvent : 1;

[tdresser, 2016/08/17 14:32:28]

This is a bit confusing. Are these events passive, or uncancellable?

Perhaps the dispatch type should be "ForcedUncancellable" not "ForcedPassive"?

[dtapuska, 2016/08/17 18:54:59]

These events aren't really passive. They are forced uncancellable. I agree we
need to clarify this.

[lanwei, 2016/08/18 12:31:47]

Delete passive or use uncancellable, non-blocking.

 
     unsigned short m_eventPhase;
     Member<EventTarget> m_currentTarget;