Don't send touch move to renderer while scrolling

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 "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "base/stl_util.h"
 
@@ skipping 83 matching lines @@
       dispatching_touch_ack_(false) {
   DCHECK(client);
 }
 
 TouchEventQueue::~TouchEventQueue() {
   if (!touch_queue_.empty())
     STLDeleteElements(&touch_queue_);
 }
 
 void TouchEventQueue::QueueEvent(const TouchEventWithLatencyInfo& event) {
+  latest_event_ = event;
   // If the queueing of |event| was triggered by an ack dispatch, defer
   // processing the event until the dispatch has finished.
   if (touch_queue_.empty() && !dispatching_touch_ack_) {
     // There is no touch event in the queue. Forward it to the renderer
     // immediately.
     touch_queue_.push_back(new CoalescedWebTouchEvent(event));
     if (ShouldForwardToRenderer(event.event))
       client_->SendTouchEventImmediately(event);
     else
       PopTouchEventWithAck(INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS);
     return;
   }
 
   // If the last queued touch-event was a touch-move, and the current event is
   // also a touch-move, then the events can be coalesced into a single event.
   if (touch_queue_.size() > 1) {
     CoalescedWebTouchEvent* last_event = touch_queue_.back();
-    if (last_event->CoalesceEventIfPossible(event))
+    if (last_event->CoalesceEventIfPossible(event)) {
+      latest_event_ = last_event->coalesced_event();
       return;
+    }
   }
   touch_queue_.push_back(new CoalescedWebTouchEvent(event));
 }
 
 void TouchEventQueue::ProcessTouchAck(InputEventAckState ack_result) {
   DCHECK(!dispatching_touch_ack_);
   if (touch_queue_.empty())
     return;
 
   // Update the ACK status for each touch point in the ACKed event.
@@ skipping 24 matching lines @@
     const TouchEventWithLatencyInfo& touch =
         touch_queue_.front()->coalesced_event();
     if (ShouldForwardToRenderer(touch.event)) {
       client_->SendTouchEventImmediately(touch);
       break;
     }
     PopTouchEventWithAck(INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS);
   }
 }
 
+void TouchEventQueue::OnGestureScrollEnd() {
+  TouchEventWithLatencyInfo end_event = GetLatestEvent();
+  FlushQueue();
+  end_event.event.type = WebKit::WebInputEvent::TouchEnd;
+  for (unsigned i = 0; i < end_event.event.touchesLength; ++i)
+    end_event.event.touches[i].state = WebKit::WebTouchPoint::StateReleased;
+  end_event.latency = ui::LatencyInfo();
+  client_->SendTouchEventImmediately(end_event);
+  ClearQueue();
+}
+
 void TouchEventQueue::FlushQueue() {
   DCHECK(!dispatching_touch_ack_);
   while (!touch_queue_.empty())
     PopTouchEventWithAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
 }
 
+void TouchEventQueue::ClearQueue() {
+  if (!touch_queue_.empty())
+    STLDeleteElements(&touch_queue_);
+}
+
 size_t TouchEventQueue::GetQueueSize() const {
   return touch_queue_.size();
 }
 
 const TouchEventWithLatencyInfo& TouchEventQueue::GetLatestEvent() const {
-  return touch_queue_.back()->coalesced_event();
+  return latest_event_;

[sadrul, 2013/08/06 19:34:19]

Why is this necessary?

 }
 
 void TouchEventQueue::PopTouchEventWithAck(InputEventAckState ack_result) {
   if (touch_queue_.empty())
     return;
   scoped_ptr<CoalescedWebTouchEvent> acked_event(touch_queue_.front());
   touch_queue_.pop_front();
 
   // Note that acking the touch-event may result in multiple gestures being sent
   // to the renderer, or touch-events being queued.
@@ skipping 29 matching lines @@
       // If the ACK status of a point is unknown, then the event should be
       // forwarded to the renderer.
       return true;
     }
   }
 
   return false;
 }
 
 }  // namespace content