Reland of [VSync Queue] Plug touch ack to gesture events and flush vsync queue if necessary

content/browser/renderer_host/ui_events_helper.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_UI_EVENTS_HELPER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_UI_EVENTS_HELPER_H_
 
 #include <memory>
 #include <vector>
 
 #include "content/browser/renderer_host/event_with_latency_info.h"
 #include "content/common/content_export.h"
+#include "content/common/input/input_event_ack_state.h"
 
 namespace ui {
 class TouchEvent;
 }
 
 namespace content {
 
 enum TouchEventCoordinateSystem {
   SCREEN_COORDINATES,
   LOCAL_COORDINATES
 };
 
 // Creates a list of ui::TouchEvents out of a single WebTouchEvent.
 // A WebTouchEvent can contain information about a number of WebTouchPoints,
 // whereas a ui::TouchEvent contains information about a single touch-point. So
 // it is possible to create more than one ui::TouchEvents out of a single
 // WebTouchEvent. All the ui::TouchEvent in the list will carry the same
 // LatencyInfo the WebTouchEvent carries.
 // |coordinate_system| specifies which fields to use for the co-ordinates,
 // WebTouchPoint.position or WebTouchPoint.screenPosition.  Is's up to the
 // caller to do any co-ordinate system mapping (typically to get them into
 // the Aura EventDispatcher co-ordinate system).
 CONTENT_EXPORT bool MakeUITouchEventsFromWebTouchEvents(
     const TouchEventWithLatencyInfo& touch,
     std::vector<std::unique_ptr<ui::TouchEvent>>* list,
     TouchEventCoordinateSystem coordinate_system);
 
+// Utility to map the event ack state from the renderer, returns true if the
+// event could be handled non-blocking.
+bool InputEventAckStateIsSetNonBlocking(InputEventAckState);
+
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_UI_EVENTS_HELPER_H_