Articulate the cancel behavior in the WebTouchEvent.

content/browser/renderer_host/input/touch_event_queue.cc

 // Copyright 2013 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/browser/renderer_host/input/touch_event_queue.h"
 
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/macros.h"
@@ skipping 28 matching lines @@
       WebInputEvent::TouchCancel,
       // TODO(rbyers): Shouldn't we use a fresh timestamp?
       event.event.timeStampSeconds,
       &event.event);
   return event;
 }
 
 bool ShouldTouchTriggerTimeout(const WebTouchEvent& event) {
   return (event.type == WebInputEvent::TouchStart ||
           event.type == WebInputEvent::TouchMove) &&
-         WebInputEventTraits::ShouldBlockEventStream(event) && event.cancelable;
+         event.dispatchType == WebInputEvent::Blocking;
 }
 
 // Compare all properties of touch points to determine the state.
 bool HasPointChanged(const WebTouchPoint& point_1,
     const WebTouchPoint& point_2) {
   DCHECK_EQ(point_1.id, point_2.id);
   if (point_1.screenPosition != point_2.screenPosition ||
       point_1.position != point_2.position ||
       point_1.radiusX != point_2.radiusX ||
       point_1.radiusY != point_2.radiusY ||
@@ skipping 536 matching lines @@
   }
 
   last_sent_touch_timestamp_sec_ = touch.event.timeStampSeconds;
 
   // Flush any pending async touch move. If it can be combined with the current
   // (touchmove) event, great, otherwise send it immediately but separately. Its
   // ack will trigger forwarding of the original |touch| event.
   if (pending_async_touchmove_) {
     if (pending_async_touchmove_->CanCoalesceWith(touch)) {
       pending_async_touchmove_->CoalesceWith(touch);
-      pending_async_touchmove_->event.cancelable = !send_touch_events_async_;
+      pending_async_touchmove_->event.dispatchType =
+          send_touch_events_async_ ? WebInputEvent::NonBlocking
+                                   : WebInputEvent::Blocking;
       touch = *pending_async_touchmove_;
       pending_async_touchmove_.reset();
     } else {
       FlushPendingAsyncTouchmove();
       return;
     }
   }
 
   // Note: Touchstart events are marked cancelable to allow transitions between
   // platform scrolling and JS pinching. Touchend events, however, remain
   // uncancelable, mitigating the risk of jank when transitioning to a fling.
   if (send_touch_events_async_ && touch.event.type != WebInputEvent::TouchStart)
-    touch.event.cancelable = false;
+    touch.event.dispatchType = WebInputEvent::NonBlocking;
 
   SendTouchEventImmediately(&touch);
 }
 
 void TouchEventQueue::FlushPendingAsyncTouchmove() {
   DCHECK(!dispatching_touch_);
   std::unique_ptr<TouchEventWithLatencyInfo> touch =
       std::move(pending_async_touchmove_);
-  touch->event.cancelable = false;
+  touch->event.dispatchType = WebInputEvent::NonBlocking;
   touch_queue_.push_front(new CoalescedWebTouchEvent(*touch, true));
   SendTouchEventImmediately(touch.get());
 }
 
 void TouchEventQueue::OnGestureScrollEvent(
     const GestureEventWithLatencyInfo& gesture_event) {
   if (gesture_event.event.type == blink::WebInputEvent::GestureScrollBegin) {
     if (has_handler_for_current_sequence_ &&
         !drop_remaining_touches_in_sequence_) {
       DCHECK(!touchmove_slop_suppressor_->suppressing_touchmoves())
@@ skipping 139 matching lines @@
     last_sent_touchevent_.reset(new WebTouchEvent(touch->event));
 
   base::AutoReset<bool> dispatching_touch(&dispatching_touch_, true);
 
   client_->SendTouchEventImmediately(*touch);
 
   // A synchronous ack will reset |dispatching_touch_|, in which case the touch
   // timeout should not be started and the count also should not be increased.
   if (dispatching_touch_) {
     if (touch->event.type == WebInputEvent::TouchMove &&
-        !touch->event.cancelable) {
+        touch->event.dispatchType != WebInputEvent::Blocking) {
       // When we send out a uncancelable touch move, we increase the count and
       // we do not process input event ack any more, we will just ack to client
       // and wait for the ack from render. Also we will remove it from the front
       // of the queue.
       ack_pending_async_touchmove_ids_.push_back(
           touch->event.uniqueTouchEventId);
       dispatching_touch_ = false;
       PopTouchEventToClient(INPUT_EVENT_ACK_STATE_IGNORED);
       TryForwardNextEventToRenderer();
       return;
@@ skipping 81 matching lines @@
     if (ack_result == INPUT_EVENT_ACK_STATE_CONSUMED)
       send_touch_events_async_ = false;
     has_handler_for_current_sequence_ |=
         ack_result != INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
   } else if (WebTouchEventTraits::IsTouchSequenceEnd(event)) {
     has_handler_for_current_sequence_ = false;
   }
 }
 
 }  // namespace content