Refactoring to share MockAudioOutputStream implementations across 3 platforms

media/audio/mac/audio_manager_mac.cc

Index: media/audio/mac/audio_manager_mac.cc
diff --git a/media/audio/mac/audio_manager_mac.cc b/media/audio/mac/audio_manager_mac.cc
index 7a8e15b8ed6859d49d9bd05b808ff532eebbcf33..a921dfbcb1b11f887681931e55081a8388b3609b 100644
--- a/media/audio/mac/audio_manager_mac.cc
+++ b/media/audio/mac/audio_manager_mac.cc
@@ -5,6 +5,7 @@
 #include <CoreAudio/AudioHardware.h>
 
 #include "base/at_exit.h"
+#include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/audio/mac/audio_output_mac.h"
 
@@ -19,8 +20,9 @@ bool AudioManagerMac::HasAudioDevices() {
 AudioOutputStream* AudioManagerMac::MakeAudioStream(Format format, int channels,
                                                     int sample_rate,
                                                     char bits_per_sample) {
-  // TODO(cpu): add mock format.
-  if (format != AUDIO_PCM_LINEAR)
+  if (format == AUDIO_MOCK)
+    return FakeAudioOutputStream::MakeFakeStream();
+  else if (format != AUDIO_PCM_LINEAR)
     return NULL;
   return new PCMQueueOutAudioOutputStream(this, channels, sample_rate,
                                           bits_per_sample);
@@ -34,19 +36,15 @@ void AudioManagerMac::UnMuteAll() {
   // TODO(cpu): implement.
 }
 
-const void* AudioManagerMac::GetLastMockBuffer() {
-  // TODO(cpu): implement.
-  return NULL;
-}
-
 // Called by the stream when it has been released by calling Close().
 void AudioManagerMac::ReleaseStream(PCMQueueOutAudioOutputStream* stream) {
   delete stream;
 }
 
 namespace {
-  AudioManagerMac* g_audio_manager = NULL;
-  
+
+AudioManagerMac* g_audio_manager = NULL;
+
 }  // namespace.
 
 void DestroyAudioManagerMac(void* param) {