Change the non-blocking event queue to the main thread event queue.

content/common/input/web_input_event_traits.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/common/input/web_input_event_traits.h"
 
 #include <bitset>
 #include <limits>
 
 #include "base/logging.h"
@@ skipping 448 matching lines @@
                event_to_coalesce,
                &event);
 }
 
 void WebInputEventTraits::Coalesce(const WebInputEvent& event_to_coalesce,
                                    WebInputEvent* event) {
   DCHECK(event);
   Apply(WebInputEventCoalesce(), event->type, event_to_coalesce, event);
 }
 
-bool WebInputEventTraits::WillReceiveAckFromRenderer(
+bool WebInputEventTraits::ShouldBlockEventOnRenderer(

[tdresser, 2016/03/15 13:41:21]

This naming is a tiny bit confusing, because it's not really that you're
blocking this event on the renderer - you're blocking the next event on getting
a response back for this event.

Perhaps just:
ShouldBlockEventStream?

[dtapuska, 2016/03/15 19:46:04]

Done.

     const WebInputEvent& event) {
   switch (event.type) {
     case WebInputEvent::MouseDown:
     case WebInputEvent::MouseUp:
     case WebInputEvent::MouseEnter:
     case WebInputEvent::MouseLeave:
     case WebInputEvent::ContextMenu:
     case WebInputEvent::GestureScrollBegin:
     case WebInputEvent::GestureScrollEnd:
     case WebInputEvent::GestureShowPress:
@@ skipping 14 matching lines @@
 
 uint32_t WebInputEventTraits::GetUniqueTouchEventId(
     const WebInputEvent& event) {
   if (WebInputEvent::isTouchEventType(event.type)) {
     return static_cast<const WebTouchEvent&>(event).uniqueTouchEventId;
   }
   return 0U;
 }
 
 }  // namespace content