Make ARMI::SwitchOutputDevice work after Stop is called.

media/base/audio_renderer_mixer_input.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.
 //
 // THREAD SAFETY
 //
 // This class is generally not thread safe. Callers should ensure thread safety.
 // For instance, the |sink_lock_| in WebAudioSourceProvider synchronizes access
 // to this object across the main thread (for WebAudio APIs) and the
 // media thread (for HTMLMediaElement APIs).
@@ skipping 82 matching lines @@
   // AudioRendererMixer obtained from mixer pool during Initialize(),
   // guaranteed to live (at least) until it is returned to the pool.
   AudioRendererMixer* mixer_;
 
   // Source of audio data which is provided to the mixer.
   AudioRendererSink::RenderCallback* callback_;
 
   // Error callback for handing to AudioRendererMixer.
   const base::Closure error_cb_;
 
-  // Pending switch-device callback, in case SwitchOutputDevice() is invoked
-  // before Start()
-  OutputDeviceStatusCB pending_switch_callback_;
-  std::string pending_switch_device_id_;
-  url::Origin pending_switch_security_origin_;
-
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerInput);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_RENDERER_MIXER_INPUT_H_