DevTools: fix concurrency problems in DevToolsFrameTraceRecorder

content/browser/devtools/devtools_frame_trace_recorder.h

 // Copyright (c) 2015 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_DEVTOOLS_DEVTOOLS_FRAME_TRACE_RECORDER_H_
 #define CONTENT_BROWSER_DEVTOOLS_DEVTOOLS_FRAME_TRACE_RECORDER_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 
 namespace cc {
 class CompositorFrameMetadata;
 }
 
 namespace content {
 
 class DevToolsFrameTraceRecorderData;
 class RenderFrameHostImpl;
 
 class DevToolsFrameTraceRecorder {
  public:
   DevToolsFrameTraceRecorder();
   ~DevToolsFrameTraceRecorder();
 
   void OnSwapCompositorFrame(
       RenderFrameHostImpl* host,
       const cc::CompositorFrameMetadata& frame_metadata);
 
  private:
-  base::WeakPtr<DevToolsFrameTraceRecorderData> last_event_data_;
+  scoped_refptr<DevToolsFrameTraceRecorderData> pending_frame_data_;
   DISALLOW_COPY_AND_ASSIGN(DevToolsFrameTraceRecorder);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_DEVTOOLS_FRAME_TRACE_RECORDER_H_