Add a silent audio sink to consume WebAudio data on silence detection.

media/base/audio_bus.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/base/audio_bus.h"
 
 #include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/limits.h"
@@ skipping 200 matching lines @@
 }
 
 void AudioBus::ZeroFrames(int frames) {
   ZeroFramesPartial(0, frames);
 }
 
 void AudioBus::Zero() {
   ZeroFrames(frames_);
 }
 
+bool AudioBus::AreFramesZero() const {
+  if (frames_ <= 0)

[DaleCurtis, 2015/06/22 19:14:41]

Seems unnecessary, loop will exit quickly anyway.

[qinmin, 2015/06/22 22:23:16]

Done.

+    return true;
+
+  for (size_t i = 0; i < channel_data_.size(); ++i) {
+    for (int j = 0; j < frames_; j++) {
+      if (*(channel_data_[i] + j) != 0.0f)

[DaleCurtis, 2015/06/22 19:14:41]

Just use "if (channel_data_[i][j]) return false;"

[qinmin, 2015/06/22 22:23:16]

Done.

+        return false;
+    }
+  }
+  return true;
+}
+
 int AudioBus::CalculateMemorySize(const AudioParameters& params) {
   return CalculateMemorySizeInternal(
       params.channels(), params.frames_per_buffer(), NULL);
 }
 
 int AudioBus::CalculateMemorySize(int channels, int frames) {
   return CalculateMemorySizeInternal(channels, frames, NULL);
 }
 
 void AudioBus::BuildChannelData(int channels, int aligned_frames, float* data) {
@@ skipping 114 matching lines @@
   return scoped_refptr<AudioBusRefCounted>(
       new AudioBusRefCounted(channels, frames));
 }
 
 AudioBusRefCounted::AudioBusRefCounted(int channels, int frames)
     : AudioBus(channels, frames) {}
 
 AudioBusRefCounted::~AudioBusRefCounted() {}
 
 }  // namespace media