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

third_party/WebKit/Source/platform/PlatformEvent.h

Index: third_party/WebKit/Source/platform/PlatformEvent.h
diff --git a/third_party/WebKit/Source/platform/PlatformEvent.h b/third_party/WebKit/Source/platform/PlatformEvent.h
index ad3883f44d3bc25ab7e9944867b6440936b58dc7..8d5cffd232cfd95058c943323e496539e5f09661 100644
--- a/third_party/WebKit/Source/platform/PlatformEvent.h
+++ b/third_party/WebKit/Source/platform/PlatformEvent.h
@@ -130,8 +130,8 @@ public:
         // All listeners are passive.
         ListenersNonBlockingPassive,
         // This value represents a state which would have normally blocking
-        // but was forced to be non-blocking.
-        ListenersForcedNonBlockingPassive,
+        // but was forced to be non-blocking during fling; not cancelable.
+        ListenersForcedNonBlockingPassiveDueToFling,

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

Are we considering these passive, or non-cancellable, or both?

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

I think they are passive and also non-cancellable. All passive events are not
cancelable. Not sure if we should replace passive with non-cancellable.

[tdresser, 2016/08/18 12:43:53]

I think I'd prefer if the word "Passive" only referred to event listeners which
the developer explicitly opted in to being passive.

Ideally this would hold true in the feedback devtools provided as well.

     };
 
     EventType type() const { return static_cast<EventType>(m_type); }