Add Needed Forward Declaration

content/renderer/media/rtc_peer_connection_handler.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_RENDERER_MEDIA_RTC_PEER_CONNECTION_HANDLER_H_
 #define CONTENT_RENDERER_MEDIA_RTC_PEER_CONNECTION_HANDLER_H_
 
 #include <map>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
 #include "content/renderer/media/webrtc/media_stream_track_metrics.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebRTCPeerConnectionHandler.h"
 #include "third_party/WebKit/public/platform/WebRTCStatsRequest.h"
 #include "third_party/WebKit/public/platform/WebRTCStatsResponse.h"
 
 namespace blink {
 class WebFrame;
 class WebRTCDataChannelHandler;
 class WebRTCOfferOptions;
+class WebRTCPeerConnectionHandlerClient;
 }
 
 namespace content {
 
 class PeerConnectionDependencyFactory;
 class PeerConnectionTracker;
 class RemoteMediaStreamImpl;
 class RtcDataChannelHandler;
 class RTCMediaConstraints;
 class WebRtcMediaStreamAdapter;
@@ skipping 207 matching lines @@
   scoped_refptr<webrtc::UMAObserver> uma_observer_;
   base::TimeTicks ice_connection_checking_start_;
   base::WeakPtrFactory<RTCPeerConnectionHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCPeerConnectionHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_PEER_CONNECTION_HANDLER_H_