Use the browser UI thread for audio on OSX.

media/base/media_switches.cc

Index: media/base/media_switches.cc
diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
index ad035568a3690843473da7ff686148aedfa0f217..98c02795db3b22eb94b5fe5bd3ae357d376a21f8 100644
--- a/media/base/media_switches.cc
+++ b/media/base/media_switches.cc
@@ -9,57 +9,63 @@ namespace switches {
 // Allow users to specify a custom buffer size for debugging purpose.
 const char kAudioBufferSize[] = "audio-buffer-size";
 
+// Enable EAC3 playback in MSE.
+const char kEnableEac3Playback[] = "enable-eac3-playback";
+
+// Enables Opus playback in media elements.
+const char kEnableOpusPlayback[] = "enable-opus-playback";
+
+// Enables VP8 Alpha playback in media elements.
+const char kEnableVp8AlphaPlayback[] = "enable-vp8-alpha-playback";
+
+// Enables VP9 playback in media elements.
+const char kEnableVp9Playback[] = "enable-vp9-playback";
+
+// Set number of threads to use for video decoding.
+const char kVideoThreads[] = "video-threads";
+
+#if defined(GOOGLE_TV)
+// Use external video surface for video with more than or equal pixels to
+// specified value. For example, value of 0 will enable external video surface
+// for all videos, and value of 921600 (=1280*720) will enable external video
+// surface for 720p video and larger.
+const char kUseExternalVideoSurfaceThresholdInPixels[] =
+    "use-external-video-surface-threshold-in-pixels";
+#endif
+
 #if defined(OS_LINUX) || defined(OS_FREEBSD) || defined(OS_SOLARIS)
-// The Alsa device to use when opening an audio stream.
-const char kAlsaOutputDevice[] = "alsa-output-device";
 // The Alsa device to use when opening an audio input stream.
 const char kAlsaInputDevice[] = "alsa-input-device";
+// The Alsa device to use when opening an audio stream.
+const char kAlsaOutputDevice[] = "alsa-output-device";
 #endif
 
-#if defined(USE_CRAS)
-// Use CRAS, the ChromeOS audio server.
-const char kUseCras[] = "use-cras";
+#if defined(OS_MACOSX)
+// Unlike other platforms, OSX requires CoreAudio calls to happen on the main
+// thread of the process.  Provide a way to disable this until support is well
+// tested.  See http://crbug.com/158170.
+// TODO(dalecurtis): Remove this once we're sure nothing has exploded.
+const char kDisableMainThreadAudio[] = "disable-main-thread-audio";
 #endif
 
 #if defined(OS_WIN)
 // Use exclusive mode audio streaming for Windows Vista and higher.
 // Leads to lower latencies for audio streams which uses the
 // AudioParameters::AUDIO_PCM_LOW_LATENCY audio path.
-// See http://msdn.microsoft.com/en-us/library/windows/desktop/dd370844(v=vs.85).aspx
+// See http://msdn.microsoft.com/en-us/library/windows/desktop/dd370844.aspx
 // for details.
 const char kEnableExclusiveAudio[] = "enable-exclusive-audio";
 
 // Use Windows WaveOut/In audio API even if Core Audio is supported.
 const char kForceWaveAudio[] = "force-wave-audio";
-#endif
-
-// Set number of threads to use for video decoding.
-const char kVideoThreads[] = "video-threads";
-
-// Enables Opus playback in media elements.
-const char kEnableOpusPlayback[] = "enable-opus-playback";
 
-// Enables VP9 playback in media elements.
-const char kEnableVp9Playback[] = "enable-vp9-playback";
-
-// Enables VP8 Alpha playback in media elements.
-const char kEnableVp8AlphaPlayback[] = "enable-vp8-alpha-playback";
-
-// Enable EAC3 playback in MSE.
-const char kEnableEac3Playback[] = "enable-eac3-playback";
-
-#if defined(OS_WIN)
+// Number of buffers to use for WaveOut.
 const char kWaveOutBuffers[] = "waveout-buffers";
 #endif
 
-#if defined(GOOGLE_TV)
-// Use external video surface for video with more than or equal pixels to
-// specified value. For example, value of 0 will enable external video surface
-// for all videos, and value of 921600 (=1280*720) will enable external video
-// surface for 720p video and larger.
-const char kUseExternalVideoSurfaceThresholdInPixels[] =
-    "use-external-video-surface-threshold-in-pixels";
+#if defined(USE_CRAS)
+// Use CRAS, the ChromeOS audio server.
+const char kUseCras[] = "use-cras";
 #endif
 
-
 }  // namespace switches