Make RTCPeerConnectionHandlerTest use the webrtc signaling thread.

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 <stddef.h>
 
 #include <map>
@@ skipping 213 matching lines @@
       webrtc::PeerConnectionInterface::IceConnectionState new_state);
 
   // Reset UMA related members to the initial state. This is invoked at the
   // constructor as well as after Ice Restart.
   void ResetUMAStats();
 
   void ReportFirstSessionDescriptions(
       const FirstSessionDescription& local,
       const FirstSessionDescription& remote);
 
-  // Virtual to allow mocks to override.
-  virtual scoped_refptr<base::SingleThreadTaskRunner> signaling_thread() const;
+  scoped_refptr<base::SingleThreadTaskRunner> signaling_thread() const;
 
   void RunSynchronousClosureOnSignalingThread(const base::Closure& closure,
                                               const char* trace_event_name);
 
   // If a track is not found with the specified id, the returned track's
   // |isNull| will return true.
   blink::WebMediaStreamTrack GetRemoteAudioTrack(
       const std::string& track_id) const;
   blink::WebMediaStreamTrack GetRemoteVideoTrack(
       const std::string& track_id) const;
@@ skipping 57 matching lines @@
   bool ice_state_seen_[webrtc::PeerConnectionInterface::kIceConnectionMax] = {};
 
   base::WeakPtrFactory<RTCPeerConnectionHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCPeerConnectionHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_PEER_CONNECTION_HANDLER_H_