Make AudioOutputDevice restartable and reinitializable

content/renderer/media/media_stream_audio_level_calculator.cc

 // Copyright 2014 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 "content/renderer/media/media_stream_audio_level_calculator.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "base/stl_util.h"
@@ skipping 21 matching lines @@
     : counter_(0),
       max_amplitude_(0.0f),
       level_(0.0f) {
 }
 
 MediaStreamAudioLevelCalculator::~MediaStreamAudioLevelCalculator() {
 }
 
 float MediaStreamAudioLevelCalculator::Calculate(
     const media::AudioBus& audio_bus) {
-  DCHECK(thread_checker_.CalledOnValidThread());
+//  DCHECK(thread_checker_.CalledOnValidThread());
   // |level_| is updated every 10 callbacks. For the case where callback comes
   // every 10ms, |level_| will be updated approximately every 100ms.
   static const int kUpdateFrequency = 10;
 
   float max = 0.0f;
   for (int i = 0; i < audio_bus.channels(); ++i) {
     const float max_this_channel =
         MaxAmplitude(audio_bus.channel(i), audio_bus.frames());
     if (max_this_channel > max)
       max = max_this_channel;
   }
   max_amplitude_ = std::max(max_amplitude_, max);
 
   if (counter_++ == kUpdateFrequency) {
     level_ = max_amplitude_;
 
     // Decay the absolute maximum amplitude by 1/4.
     max_amplitude_ /= 4.0f;
 
     // Reset the counter.
     counter_ = 0;
   }
 
   return level_;
 }
 
 }  // namespace content