Change DtmfSenderHandler to handle events on the signaling thread.

content/renderer/media/rtc_dtmf_sender_handler.h

 // Copyright (c) 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_RENDERER_MEDIA_RTC_DTMF_SENDER_HANDLER_H_
 #define CONTENT_RENDERER_MEDIA_RTC_DTMF_SENDER_HANDLER_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/platform/WebRTCDTMFSenderHandler.h"
 #include "third_party/WebKit/public/platform/WebRTCDTMFSenderHandlerClient.h"
 #include "third_party/libjingle/source/talk/app/webrtc/dtmfsenderinterface.h"
 
 namespace content {
 
 // RtcDtmfSenderHandler is a delegate for the RTC DTMF Sender API messages
 // going between WebKit and native DTMF Sender in libjingle.
 // Instances of this class are owned by WebKit.
 // WebKit call all of these methods on the main render thread.
 // Callbacks to the webrtc::DtmfSenderObserverInterface implementation also
 // occur on the main render thread.
 class CONTENT_EXPORT RtcDtmfSenderHandler
     : NON_EXPORTED_BASE(public blink::WebRTCDTMFSenderHandler),
-      NON_EXPORTED_BASE(public webrtc::DtmfSenderObserverInterface),
       NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
   explicit RtcDtmfSenderHandler(webrtc::DtmfSenderInterface* dtmf_sender);
   virtual ~RtcDtmfSenderHandler();
 
   // blink::WebRTCDTMFSenderHandler implementation.
-  virtual void setClient(
+  void setClient(
       blink::WebRTCDTMFSenderHandlerClient* client) override;
-  virtual blink::WebString currentToneBuffer() override;
-  virtual bool canInsertDTMF() override;
-  virtual bool insertDTMF(const blink::WebString& tones, long duration,
+  blink::WebString currentToneBuffer() override;
+  bool canInsertDTMF() override;
+  bool insertDTMF(const blink::WebString& tones, long duration,
                           long interToneGap) override;
 
-  // webrtc::DtmfSenderObserverInterface implementation.
-  void OnToneChange(const std::string& tone) override;
+  void OnToneChange(const std::string& tone);
 
  private:
+  class Observer;
+  scoped_refptr<Observer> observer_;
   scoped_refptr<webrtc::DtmfSenderInterface> dtmf_sender_;
   blink::WebRTCDTMFSenderHandlerClient* webkit_client_;
+  base::WeakPtrFactory<RtcDtmfSenderHandler> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_DTMF_SENDER_HANDLER_H_