Wheel scroll latching enabled behind flag.

ui/events/blink/input_handler_proxy.cc

Index: ui/events/blink/input_handler_proxy.cc
diff --git a/ui/events/blink/input_handler_proxy.cc b/ui/events/blink/input_handler_proxy.cc
index 821a38625a91a6bd85f23fb2bc89304939bdebc0..e128193c8c02e86acd7db610d989350e41461a23 100644
--- a/ui/events/blink/input_handler_proxy.cc
+++ b/ui/events/blink/input_handler_proxy.cc
@@ -131,6 +131,10 @@ cc::ScrollState CreateScrollStateForGesture(const WebGestureEvent& event) {
       scroll_state_data.position_x = event.x;
       scroll_state_data.position_y = event.y;
       scroll_state_data.is_beginning = true;
+      // In Mac flings are also scrolls.

[tdresser, 2016/07/25 16:46:55]

Why is there still Mac specific code?

[sahel, 2016/07/25 17:58:26]

The code is not mac specific. if the inertialPhase of a scrollBegin event is
momentumPhase, it means the scroll begin is for a fling and it happens on
devices that don't send a different type of event for flings.
I deleted this part of change for this cl.

+      if (event.data.scrollBegin.inertialPhase ==
+          WebGestureEvent::MomentumPhase)
+        scroll_state_data.is_in_inertial_phase = true;
       break;
     case WebInputEvent::GestureFlingStart:
       scroll_state_data.velocity_x = event.data.flingStart.velocityX;