Make touch events uncancelable during fling when they are on the current active scroll layer

cc/input/event_listener_properties.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_INPUT_EVENT_LISTENER_PROPERTIES_H_
 #define CC_INPUT_EVENT_LISTENER_PROPERTIES_H_
 
 namespace cc {
 
 enum class EventListenerClass {
   // This value includes "touchstart", "touchmove", and "pointer" events.
   kTouchStartOrMove,
   // This value includes "wheel" and "mousewheel" events.
   kMouseWheel,
   // This value includes "touchend" and "touchcancel" events.
   kTouchEndOrCancel,
   kNumClasses
 };
 
 enum class EventListenerProperties {
   kNone,
   kPassive,
   kBlocking,
   kBlockingAndPassive,

[dtapuska, 2016/11/21 19:19:30]

I have a problem with this enum not matching the blink enum now.

https://cs.chromium.org/chromium/src/content/renderer/gpu/render_widget_compo...

The new method doesn't ever return kPassive. 

I wonder if we really should just return a special enum for this method that you
added; it could have very similar constants to this. But using the enum is
dangerous as it is statically cast and checked between blink and CC. (although
it appears to be missing a static size check for kMax which would have caught
this discrepency).

[lanwei, 2016/11/23 21:57:38]

Done.

+  kBlockingAndMaybePassiveDueToFling,
   kMax
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_EVENT_LISTENER_PROPERTIES_H_