Revert of Fix getUserMedia so that failure is reported for invalid audio sources.

content/renderer/media/external_media_stream_audio_source.h

 // Copyright 2016 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_EXTERNAL_MEDIA_STREAM_AUDIO_SOURCE_H_
 #define CONTENT_RENDERER_MEDIA_EXTERNAL_MEDIA_STREAM_AUDIO_SOURCE_H_
 
 #include "content/renderer/media/media_stream_audio_source.h"
 
 #include "media/base/audio_capturer_source.h"
@@ skipping 17 matching lines @@
       bool is_remote);
 
   ~ExternalMediaStreamAudioSource() final;
 
  private:
   // MediaStreamAudioSource implementation.
   bool EnsureSourceIsStarted() final;
   void EnsureSourceIsStopped() final;
 
   // media::AudioCapturerSource::CaptureCallback implementation.
-  void OnCaptureStarted() final;
   void Capture(const media::AudioBus* audio_bus,
                int audio_delay_milliseconds,
                double volume,
                bool key_pressed) final;
   void OnCaptureError(const std::string& message) final;
 
   // The external source provided to the constructor.
   scoped_refptr<media::AudioCapturerSource> source_;
 
   // In debug builds, check that all methods that could cause object graph
   // or data flow changes are being called on the main thread.
   base::ThreadChecker thread_checker_;
 
   // True once the source has been started successfully.
   bool was_started_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalMediaStreamAudioSource);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_EXTERNAL_MEDIA_STREAM_AUDIO_SOURCE_H_