[Android] Properly disable the touch ack timeout during a touch sequence

content/browser/renderer_host/input/touch_event_queue.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_TOUCH_EVENT_QUEUE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 75 matching lines @@
       InputEventAckState ack_result);
 
   // Notifies the queue whether the renderer has at least one touch handler.
   void OnHasTouchEventHandlers(bool has_handlers);
 
   // Returns whether the currently pending touch event (waiting ACK) is for
   // a touch start event.
   bool IsPendingAckTouchStart() const;
 
   // Sets whether a delayed touch ack will cancel and flush the current
-  // touch sequence.
+  // touch sequence. Note that, if the timeout was previously disabled, enabling
+  // it will take effect only for the following touch sequence.
   void SetAckTimeoutEnabled(bool enabled, size_t ack_timeout_delay_ms);
 
   bool empty() const WARN_UNUSED_RESULT {
     return touch_queue_.empty();
   }
 
   size_t size() const {
     return touch_queue_.size();
   }
 
@@ skipping 90 matching lines @@
   // setting for experimentation, but we may evolve it into an app-controlled
   // mode.
   const TouchScrollingMode touch_scrolling_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_