Shutdown PeerConnectionDependencyFactory before Blink shutdown

content/renderer/media/webrtc/peer_connection_dependency_factory.h

Index: content/renderer/media/webrtc/peer_connection_dependency_factory.h
diff --git a/content/renderer/media/webrtc/peer_connection_dependency_factory.h b/content/renderer/media/webrtc/peer_connection_dependency_factory.h
index 0486380138657892eb93510be53064cc23b99760..8bfa9e51e503fe63619d5f826fb066eb48f6571e 100644
--- a/content/renderer/media/webrtc/peer_connection_dependency_factory.h
+++ b/content/renderer/media/webrtc/peer_connection_dependency_factory.h
@@ -9,7 +9,6 @@
 
 #include "base/files/file.h"
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread.h"
 #include "content/common/content_export.h"
@@ -55,12 +54,11 @@ struct StreamDeviceInfo;
 
 // Object factory for RTC PeerConnections.
 class CONTENT_EXPORT PeerConnectionDependencyFactory
-    : NON_EXPORTED_BASE(base::MessageLoop::DestructionObserver),
-      NON_EXPORTED_BASE(public base::NonThreadSafe) {
+    : NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
   PeerConnectionDependencyFactory(
       P2PSocketDispatcher* p2p_socket_dispatcher);
-  ~PeerConnectionDependencyFactory() override;
+  virtual ~PeerConnectionDependencyFactory();
 
   // Create a RTCPeerConnectionHandler object that implements the
   // WebKit WebRTCPeerConnectionHandler interface.
@@ -114,6 +112,7 @@ class CONTENT_EXPORT PeerConnectionDependencyFactory
   scoped_refptr<base::SingleThreadTaskRunner> GetWebRtcWorkerThread() const;
   virtual scoped_refptr<base::SingleThreadTaskRunner> GetWebRtcSignalingThread()
       const;
+  void ShutDown();
 
  protected:
   // Asks the PeerConnection factory to create a Local VideoTrack object with
@@ -130,11 +129,6 @@ class CONTENT_EXPORT PeerConnectionDependencyFactory
   void EnsureWebRtcAudioDeviceImpl();
 
  private:
-  // Implement base::MessageLoop::DestructionObserver.
-  // This makes sure the libjingle PeerConnectionFactory is released before
-  // the renderer message loop is destroyed.
-  void WillDestroyCurrentMessageLoop() override;
-
   // Functions related to Stun probing trial to determine how fast we could send
   // Stun request without being dropped by NAT.
   void TryScheduleStunProbeTrial();