Coalesce async touch move events until the ack back from render

content/browser/renderer_host/input/input_router_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_IMPL_H_
 
 #include <queue>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "content/browser/renderer_host/input/gesture_event_queue.h"
 #include "content/browser/renderer_host/input/input_router.h"
 #include "content/browser/renderer_host/input/touch_action_filter.h"
 #include "content/browser/renderer_host/input/touch_event_queue.h"
 #include "content/browser/renderer_host/input/touchpad_tap_suppression_controller.h"
 #include "content/common/input/input_event_stream_validator.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 
 struct InputHostMsg_HandleInputEvent_ACK_Params;
+struct InputHostMsg_HandleUncancelableTouchMoveEvent_ACK_Params;
 
 namespace IPC {
 class Sender;
 }
 
 namespace ui {
 struct LatencyInfo;
 }
 
 namespace content {
@@ skipping 86 matching lines @@
                      const ui::LatencyInfo& latency_info);
 
   // Returns true if |input_event| was successfully sent to the renderer
   // as an async IPC Message.
   bool OfferToRenderer(const blink::WebInputEvent& input_event,
                        const ui::LatencyInfo& latency_info,
                        bool is_keyboard_shortcut);
 
   // IPC message handlers
   void OnInputEventAck(const InputHostMsg_HandleInputEvent_ACK_Params& ack);
+  void OnUncancelableTouchMoveAck(
+      const InputHostMsg_HandleUncancelableTouchMoveEvent_ACK_Params& ack);
   void OnDidOverscroll(const DidOverscrollParams& params);
   void OnMsgMoveCaretAck();
   void OnSelectMessageAck();
   void OnHasTouchEventHandlers(bool has_handlers);
   void OnSetTouchAction(TouchAction touch_action);
 
   // Indicates the source of an ack provided to |ProcessInputEventAck()|.
   // The source is tracked by |current_ack_source_|, which aids in ack routing.
   enum AckSource {
     RENDERER,
@@ skipping 115 matching lines @@
   TouchActionFilter touch_action_filter_;
   InputEventStreamValidator input_stream_validator_;
   InputEventStreamValidator output_stream_validator_;
 
   DISALLOW_COPY_AND_ASSIGN(InputRouterImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_IMPL_H_