Allow pass through buffer sizes on OSX.

media/base/audio_hardware_config.cc

 // Copyright (c) 2013 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_hardware_config.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "build/build_config.h"
@@ skipping 81 matching lines @@
 }
 
 void AudioHardwareConfig::UpdateOutputConfig(
     const AudioParameters& output_params) {
   AutoLock auto_lock(config_lock_);
   output_params_ = output_params;
 }
 
 int AudioHardwareConfig::GetHighLatencyBufferSize() const {
   AutoLock auto_lock(config_lock_);
-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(OS_MACOSX)
   // Empirically, use the nearest higher power of two buffer size corresponding
   // to 20 ms worth of samples.  For a given sample rate, this works out to:
   //
   //     <= 3200   : 64
   //     <= 6400   : 128
   //     <= 12800  : 256
   //     <= 25600  : 512
   //     <= 51200  : 1024
   //     <= 102400 : 2048
   //     <= 204800 : 4096
   //
   // On Linux, the minimum hardware buffer size is 512, so the lower calculated
   // values are unused.  OSX may have a value as low as 128.  Windows is device
   // dependent but will generally be sample_rate() / 100.
   const int high_latency_buffer_size =
       RoundUpToPowerOfTwo(2 * output_params_.sample_rate() / 100);
   return std::max(output_params_.frames_per_buffer(), high_latency_buffer_size);
 #else
   return output_params_.frames_per_buffer();
 #endif
 }
 
 }  // namespace media