Remove pure-virtual MediaStreamProvider::Unregister method and make overrides non-virtual.

content/browser/renderer_host/media/audio_input_device_manager.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.
 //
 // AudioInputDeviceManager manages the audio input devices. In particular it
 // communicates with MediaStreamManager and AudioInputRendererHost on the
 // browser IO thread, handles queries like
 // enumerate/open/close/GetOpenedDeviceInfoById from MediaStreamManager and
 // GetOpenedDeviceInfoById from AudioInputRendererHost.
 // The work for enumerate/open/close is handled asynchronously on Media Stream
@@ skipping 26 matching lines @@
   // AudioInputDeviceManager before MediaStream is implemented.
   // TODO(xians): Remove it when the webrtc unittest does not need it any more.
   static const int kFakeOpenSessionId;
 
   explicit AudioInputDeviceManager(media::AudioManager* audio_manager);
 
   // Gets the opened device info by |session_id|. Returns NULL if the device
   // is not opened, otherwise the opened device. Called on IO thread.
   const StreamDeviceInfo* GetOpenedDeviceInfoById(int session_id);
 
+  void Unregister();
+
   // MediaStreamProvider implementation, called on IO thread.
   void Register(MediaStreamProviderListener* listener,
                 const scoped_refptr<base::SingleThreadTaskRunner>&
                     device_task_runner) override;
-  void Unregister() override;
   void EnumerateDevices(MediaStreamType stream_type) override;
   int Open(const StreamDeviceInfo& device) override;
   void Close(int session_id) override;
 
   void UseFakeDevice();
   bool ShouldUseFakeDevice() const;
 
 #if defined(OS_CHROMEOS)
   // Registers and unregisters that a stream using keyboard mic has been opened
   // or closed. Keeps count of how many such streams are open and activates and
@@ skipping 56 matching lines @@
 
   // The message loop of media stream device thread that this object runs on.
   scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioInputDeviceManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_H_