Add a completion callback to gpuBenchmarking.beginSmoothScroll

content/port/browser/smooth_scroll_gesture.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_PORT_BROWSER_SMOOTH_SCROLL_GESTURE_H_
 #define CONTENT_PORT_BROWSER_SMOOTH_SCROLL_GESTURE_H_
 
+#include "base/memory/ref_counted.h"
 #include "base/time.h"
 
 namespace content {
 
 class RenderWidgetHost;
 
 // This is a base class representing a single scroll gesture. These gestures are
 // paired with the rendering benchmarking system to (automatically) measure how
 // smoothnly chrome is responding to user input.
-class SmoothScrollGesture {
+class SmoothScrollGesture : public base::RefCounted<SmoothScrollGesture> {
  public:
-  virtual ~SmoothScrollGesture() {}
 
   // When called, the gesture should compute its state at the provided timestamp
   // and send the right input events to the provided RenderWidgetHost to
   // simulate the gesture having run up to that point in time.
   //
   // This function should return true until the gesture is over. A false return
   // value will stop ticking the gesture and clean it up.
   virtual bool ForwardInputEvents(base::TimeTicks now,
                                   RenderWidgetHost* host) = 0;
+ protected:
+  friend class base::RefCounted<SmoothScrollGesture>;
+  virtual ~SmoothScrollGesture() {}
 };
 
 } // namespace content
 
 #endif // CONTENT_PORT_BROWSER_SMOOTH_SCROLL_GESTURE_H_