Crash fix: Remove MessageLoop from AudioPowerMonitor and instead use MessageLoopProxy in AudioOutpu…

media/audio/audio_output_controller.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 MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/atomic_ref_count.h"
 #include "base/callback.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/timer/timer.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager.h"
+#include "media/audio/audio_power_monitor.h"
 #include "media/audio/audio_source_diverter.h"
 #include "media/audio/simple_sources.h"
 #include "media/base/media_export.h"
 
 // An AudioOutputController controls an AudioOutputStream and provides data
 // to this output stream. It has an important function that it executes
 // audio operations like play, pause, stop, etc. on a separate thread,
 // namely the audio manager thread.
 //
 // All the public methods of AudioOutputController are non-blocking.
@@ skipping 20 matching lines @@
 // all functionally equivalent and require a Play() call to continue to the next
 // state.
 //
 // The AudioOutputStream can request data from the AudioOutputController via the
 // AudioSourceCallback interface. AudioOutputController uses the SyncReader
 // passed to it via construction to synchronously fulfill this read request.
 //
 
 namespace media {
 
-class AudioPowerMonitor;
-
 class MEDIA_EXPORT AudioOutputController
     : public base::RefCountedThreadSafe<AudioOutputController>,
       public AudioOutputStream::AudioSourceCallback,
       public AudioSourceDiverter,
       NON_EXPORTED_BASE(public AudioManager::AudioDeviceListener)  {
  public:
   // An event handler that receives events from the AudioOutputController. The
   // following methods are called on the audio manager thread.
   class MEDIA_EXPORT EventHandler {
    public:
@@ skipping 107 matching lines @@
   // The following methods are executed on the audio manager thread.
   void DoCreate(bool is_for_device_change);
   void DoPlay();
   void DoPause();
   void DoClose();
   void DoSetVolume(double volume);
   void DoReportError();
   void DoStartDiverting(AudioOutputStream* to_stream);
   void DoStopDiverting();
 
-  // Called at regular intervals during playback to check for a change in
-  // silence and call EventHandler::OnAudible() when state changes occur.
-  void MaybeInvokeAudibleCallback();
+  // Calls EventHandler::OnPowerMeasured() with the current power level and then
+  // schedules itself to be called again later.
+  void ReportPowerMeasurementPeriodically();
 
   // Helper method that stops the physical stream.
   void StopStream();
 
   // Helper method that stops, closes, and NULLs |*stream_|.
   void DoStopCloseAndClearStream();
 
   // Sanity-check that entry/exit to OnMoreIOData() by the hardware audio thread
   // happens only between AudioOutputStream::Start() and Stop().
   void AllowEntryToOnMoreIOData();
@@ skipping 29 matching lines @@
   // SyncReader is used only in low latency mode for synchronous reading.
   SyncReader* const sync_reader_;
 
   // The message loop of audio manager thread that this object runs on.
   const scoped_refptr<base::MessageLoopProxy> message_loop_;
 
   // When starting stream we wait for data to become available.
   // Number of times left.
   int number_polling_attempts_left_;
 
-  // Scans audio samples from OnMoreIOData() as input and causes
-  // EventHandler::OnPowerMeasured() to be called with power level measurements
-  // at regular intervals.
-  scoped_ptr<AudioPowerMonitor> power_monitor_;
-  base::CancelableCallback<void(float, bool)> power_monitor_callback_;
+  // Scans audio samples from OnMoreIOData() as input to compute power levels.
+  AudioPowerMonitor power_monitor_;
+
+  // Periodic callback to report power levels during playback.
+  base::CancelableClosure power_poll_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_