Attempting to resolve a race condition with PowerMonitor

media/audio/mac/audio_manager_mac.cc

 // 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.
 
 #include "media/audio/mac/audio_manager_mac.h"
 
 #include <CoreAudio/AudioHardware.h>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 208 matching lines @@
     // has already been stopped.
     (*it)->Stop();
   }
   streams->clear();
 }
 
 class AudioManagerMac::AudioPowerObserver : public base::PowerObserver {
  public:
   AudioPowerObserver()
       : is_suspending_(false),
-        is_monitoring_(base::PowerMonitor::Get()) {
+        is_monitoring_(base::PowerMonitor::IsInitialized()) {
     // The PowerMonitor requires signifcant setup (a CFRunLoop and preallocated
     // IO ports) so it's not available under unit tests.  See the OSX impl of
     // base::PowerMonitorDeviceSource for more details.
     if (!is_monitoring_)
       return;
-    base::PowerMonitor::Get()->AddObserver(this);
+    base::PowerMonitor::AddObserver(this);
   }
 
   virtual ~AudioPowerObserver() {
     DCHECK(thread_checker_.CalledOnValidThread());
     if (!is_monitoring_)
       return;
-    base::PowerMonitor::Get()->RemoveObserver(this);
+    base::PowerMonitor::RemoveObserver(this);
   }
 
   bool ShouldDeferOutputStreamStart() {
     DCHECK(thread_checker_.CalledOnValidThread());
     // Start() should be deferred if the system is in the middle of a suspend or
     // has recently started the process of resuming.
     return is_suspending_ || base::TimeTicks::Now() < earliest_start_time_;
   }
 
  private:
@@ skipping 523 matching lines @@
 void AudioManagerMac::ReleaseInputStream(AudioInputStream* stream) {
   input_streams_.remove(stream);
   AudioManagerBase::ReleaseInputStream(stream);
 }
 
 AudioManager* CreateAudioManager(AudioLogFactory* audio_log_factory) {
   return new AudioManagerMac(audio_log_factory);
 }
 
 }  // namespace media