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

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 18baa4cf33d4dd8cbcc16699b89b28e4d6451d49..3454dd72d2656bf76f40a668726e81cb42a755b6 100644
--- a/ui/events/blink/input_handler_proxy.cc
+++ b/ui/events/blink/input_handler_proxy.cc
@@ -835,12 +835,20 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleGestureFlingStart(
 InputHandlerProxy::EventDisposition InputHandlerProxy::HandleTouchStart(
     const blink::WebTouchEvent& touch_event) {
   EventDisposition result = DROP_EVENT;
+  bool maybe_passive_due_to_fling = false;
   for (size_t i = 0; i < touch_event.touchesLength; ++i) {
     if (touch_event.touches[i].state != WebTouchPoint::StatePressed)
       continue;
-    if (input_handler_->DoTouchEventsBlockScrollAt(
+    cc::EventListenerProperties event_result =
+        input_handler_->DoTouchHandlersBlockScrollAt(
             gfx::Point(touch_event.touches[i].position.x,
-                       touch_event.touches[i].position.y))) {
+                       touch_event.touches[i].position.y));
+    if (event_result != cc::EventListenerProperties::kNone) {
+      maybe_passive_due_to_fling =
+          event_result ==
+                  cc::EventListenerProperties::kBlockingAndPassiveDueToFling
+              ? true

[bokan, 2016/11/15 22:42:40]

No need for ? true : false

[lanwei, 2016/11/16 21:13:29]

Done.

+              : false;
       result = DID_NOT_HANDLE;
       break;
     }
@@ -892,7 +900,8 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleTouchStart(
   }
 
   bool is_fling_on_impl = fling_curve_ && !fling_may_be_active_on_main_thread_;
-  if (result == DID_NOT_HANDLE && is_fling_on_impl)
+  if (result == DID_NOT_HANDLE && is_fling_on_impl &&
+      maybe_passive_due_to_fling)
     result = DID_NOT_HANDLE_NON_BLOCKING_DUE_TO_FLING;
 
   return result;