Coalesce async touch move events until the ack back from render

content/browser/renderer_host/input/input_router_impl_perftest.cc

 // Copyright 2014 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 "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/renderer_host/input/input_ack_handler.h"
 #include "content/browser/renderer_host/input/input_router_client.h"
 #include "content/browser/renderer_host/input/input_router_impl.h"
 #include "content/common/input/web_input_event_traits.h"
@@ skipping 215 matching lines @@
     input_router_->SendGestureEvent(
         GestureEventWithLatencyInfo(gesture, latency));
   }
 
   void SendEvent(const WebTouchEvent& touch, const ui::LatencyInfo& latency) {
     input_router_->SendTouchEvent(TouchEventWithLatencyInfo(touch, latency));
   }
 
   void SendEventAckIfNecessary(const blink::WebInputEvent& event,
                                InputEventAckState ack_result) {
-    if (WebInputEventTraits::IgnoresAckDisposition(event))
+    if (!WebInputEventTraits::WillReceiveAckFromRenderer(event))
       return;
-    InputHostMsg_HandleInputEvent_ACK_Params ack;
-    ack.type = event.type;
-    ack.state = ack_result;
+    InputEventAck ack(event.type, ack_result);
     InputHostMsg_HandleInputEvent_ACK response(0, ack);
     input_router_->OnMessageReceived(response);
   }
 
   void OnHasTouchEventHandlers(bool has_handlers) {
     input_router_->OnMessageReceived(
         ViewHostMsg_HasTouchEventHandlers(0, has_handlers));
   }
 
   size_t GetAndResetSentEventCount() {
@@ skipping 125 matching lines @@
 
 TEST_F(InputRouterImplPerfTest, TouchSwipeToGestureScroll) {
   SimulateTouchAndScrollEventSequence("TouchSwipeToGestureScroll ",
                                       kDefaultSteps,
                                       kDefaultOrigin,
                                       kDefaultDistance,
                                       kDefaultIterations);
 }
 
 }  // namespace content