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

content/renderer/input/main_thread_event_queue.cc

 // 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.
 
 #include "content/renderer/input/main_thread_event_queue.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "content/common/input/event_with_latency_info.h"
 #include "content/common/input_messages.h"
 
@@ skipping 50 matching lines @@
 
 MainThreadEventQueue::SharedState::~SharedState() {}
 
 MainThreadEventQueue::MainThreadEventQueue(
     int routing_id,
     MainThreadEventQueueClient* client,
     const scoped_refptr<base::SingleThreadTaskRunner>& main_task_runner,
     blink::scheduler::RendererScheduler* renderer_scheduler)
     : routing_id_(routing_id),
       client_(client),
-      is_flinging_(false),
       last_touch_start_forced_nonblocking_due_to_fling_(false),
       enable_fling_passive_listener_flag_(base::FeatureList::IsEnabled(
           features::kPassiveEventListenersDueToFling)),
       handle_raf_aligned_touch_input_(
           base::FeatureList::IsEnabled(features::kRafAlignedTouchInputEvents)),
       handle_raf_aligned_mouse_input_(
           base::FeatureList::IsEnabled(features::kRafAlignedMouseInputEvents)),
       main_task_runner_(main_task_runner),
       renderer_scheduler_(renderer_scheduler) {}
 
 MainThreadEventQueue::~MainThreadEventQueue() {}
 
 bool MainThreadEventQueue::HandleEvent(
     ui::ScopedWebInputEvent event,
     const ui::LatencyInfo& latency,
     InputEventDispatchType original_dispatch_type,
     InputEventAckState ack_result) {
   DCHECK(original_dispatch_type == DISPATCH_TYPE_BLOCKING ||
          original_dispatch_type == DISPATCH_TYPE_NON_BLOCKING);
   DCHECK(ack_result == INPUT_EVENT_ACK_STATE_SET_NON_BLOCKING ||
-         ack_result == INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+         ack_result == INPUT_EVENT_ACK_STATE_NOT_CONSUMED ||
+         INPUT_EVENT_ACK_STATE_NOT_CONSUMED_NON_BLOCKING);
 
   bool non_blocking = original_dispatch_type == DISPATCH_TYPE_NON_BLOCKING ||
                       ack_result == INPUT_EVENT_ACK_STATE_SET_NON_BLOCKING;
   bool is_wheel = event->type == blink::WebInputEvent::MouseWheel;
   bool is_touch = blink::WebInputEvent::isTouchEventType(event->type);
 
   if (is_touch) {
     blink::WebTouchEvent* touch_event =
         static_cast<blink::WebTouchEvent*>(event.get());
-    touch_event->dispatchedDuringFling = is_flinging_;
+
     // Adjust the |dispatchType| on the event since the compositor
     // determined all event listeners are passive.
     if (non_blocking) {
       touch_event->dispatchType =
           blink::WebInputEvent::ListenersNonBlockingPassive;
     }
     if (touch_event->type == blink::WebInputEvent::TouchStart)
       last_touch_start_forced_nonblocking_due_to_fling_ = false;
 
     if (enable_fling_passive_listener_flag_ &&
         touch_event->touchStartOrFirstTouchMove &&
         touch_event->dispatchType == blink::WebInputEvent::Blocking) {
       // If the touch start is forced to be passive due to fling, its following
       // touch move should also be passive.
-      if (is_flinging_ || last_touch_start_forced_nonblocking_due_to_fling_) {
+      if (ack_result == INPUT_EVENT_ACK_STATE_NOT_CONSUMED_NON_BLOCKING ||
+          last_touch_start_forced_nonblocking_due_to_fling_) {
         touch_event->dispatchType =
             blink::WebInputEvent::ListenersForcedNonBlockingDueToFling;
         non_blocking = true;
         last_touch_start_forced_nonblocking_due_to_fling_ = true;
       }
     }
   }
   if (is_wheel && non_blocking) {
     // Adjust the |dispatchType| on the event since the compositor
     // determined all event listeners are passive.
@@ skipping 175 matching lines @@
       // additional frame.
       return static_cast<const blink::WebTouchEvent&>(event->event())
                      .dispatchType != blink::WebInputEvent::Blocking &&
              handle_raf_aligned_touch_input_;
     default:
       return false;
   }
 }
 
 }  // namespace content