Make tapDown async.

content/browser/renderer_host/input/immediate_input_router.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/immediate_input_router.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "content/browser/renderer_host/input/gesture_event_filter.h"
 #include "content/browser/renderer_host/input/input_ack_handler.h"
@@ skipping 467 matching lines @@
           = next_mouse_move_.Pass();
       SendMouseEvent(*next_mouse_move);
     }
   } else if (WebInputEvent::isKeyboardEventType(type)) {
     ProcessKeyboardAck(type, ack_result);
   } else if (type == WebInputEvent::MouseWheel) {
     ProcessWheelAck(ack_result);
   } else if (WebInputEvent::isTouchEventType(type)) {
     ProcessTouchAck(ack_result, latency_info);
   } else if (WebInputEvent::isGestureEventType(type)) {
-    ProcessGestureAck(type, ack_result);
+    ProcessGestureAck(event_type, ack_result);
   }
 
   // WARNING: |this| may be deleted at this point.
 
   // This is used only for testing, and the other end does not use the
   // source object.  On linux, specifying
   // Source<RenderWidgetHost> results in a very strange
   // runtime error in the epilogue of the enclosing
   // (ProcessInputEventAck) method, but not on other platforms; using
   // 'void' instead is just as safe (since NotificationSource
@@ skipping 35 matching lines @@
 
   // Now send the next (coalesced) mouse wheel event.
   if (!coalesced_mouse_wheel_events_.empty()) {
     MouseWheelEventWithLatencyInfo next_wheel_event =
         coalesced_mouse_wheel_events_.front();
     coalesced_mouse_wheel_events_.pop_front();
     SendWheelEvent(next_wheel_event);
   }
 }
 
-void ImmediateInputRouter::ProcessGestureAck(int type,
+void ImmediateInputRouter::ProcessGestureAck(WebInputEvent::Type type,
                                              InputEventAckState ack_result) {
+  if (GestureEventFilter::IsGestureEventTypeAsync(type))
+    return;

[jdduke (slow), 2013/10/01 17:16:15]

As we discussed, please add a comment here indicating the importance of order
for ack dispatch to |ack_handler_| and |gesture_event_filter_|, so somebody
doesn't fiddle with this condition.

[tdresser, 2013/10/01 17:54:36]

Done.

   const bool processed = (INPUT_EVENT_ACK_STATE_CONSUMED == ack_result);
   ack_handler_->OnGestureEventAck(
       gesture_event_filter_->GetGestureEventAwaitingAck(), ack_result);
   gesture_event_filter_->ProcessGestureAck(processed, type);
 }
 
 void ImmediateInputRouter::ProcessTouchAck(
     InputEventAckState ack_result,
     const ui::LatencyInfo& latency_info) {
   // |touch_event_queue_| will forward to OnTouchEventAck when appropriate.
   touch_event_queue_->ProcessTouchAck(ack_result, latency_info);
 }
 
 void ImmediateInputRouter::HandleGestureScroll(
     const GestureEventWithLatencyInfo& gesture_event) {
   if (!enable_no_touch_to_renderer_while_scrolling_)
     return;
 
   // Once scrolling is started stop forwarding touch move events to renderer.
   if (gesture_event.event.type == WebInputEvent::GestureScrollBegin)
     touch_event_queue_->set_no_touch_move_to_renderer(true);
 
   if (gesture_event.event.type == WebInputEvent::GestureScrollEnd ||
       gesture_event.event.type == WebInputEvent::GestureFlingStart) {
     touch_event_queue_->set_no_touch_move_to_renderer(false);
   }
 }
 
 }  // namespace content