Gardening: Revert "Use AudioStreamMonitor to control power save blocking."

content/public/browser/media_observer.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_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
 
 #include "base/callback_forward.h"
 #include "content/public/browser/media_request_state.h"
 #include "content/public/common/media_stream_request.h"
@@ skipping 16 matching lines @@
       int render_frame_id,
       int page_request_id,
       const GURL& security_origin,
       MediaStreamType stream_type,
       MediaRequestState state) = 0;
 
   // Called when an audio stream is being created.
   virtual void OnCreatingAudioStream(int render_process_id,
                                      int render_frame_id) = 0;
 
+  // Called when an audio stream transitions into a playing state.
+  // |power_read_callback| is a thread-safe callback, provided for polling the
+  // current audio signal power level, and any copies/references to it must be
+  // destroyed when OnAudioStreamStopped() is called.
+  //
+  // The callback returns the current power level (in dBFS units) and the clip
+  // status (true if any part of the audio signal has clipped since the last
+  // callback run).  See media/audio/audio_power_monitor.h for more info.
+  typedef base::Callback<std::pair<float, bool>()> ReadPowerAndClipCallback;
+  virtual void OnAudioStreamPlaying(
+      int render_process_id,
+      int render_frame_id,
+      int stream_id,
+      const ReadPowerAndClipCallback& power_read_callback) = 0;
+
+  // Called when an audio stream has stopped.
+  virtual void OnAudioStreamStopped(
+      int render_process_id,
+      int render_frame_id,
+      int stream_id) = 0;
+
  protected:
   virtual ~MediaObserver() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_