Prevent AudioLowLatencyInputMac from changing frame sizes.

media/audio/mac/audio_low_latency_input_mac.cc

Index: media/audio/mac/audio_low_latency_input_mac.cc
diff --git a/media/audio/mac/audio_low_latency_input_mac.cc b/media/audio/mac/audio_low_latency_input_mac.cc
index dc9bd8ab48ee7d87aa52a690b407fa3da2cc2ec1..9bee5a4ba583fc0ff8c6ca035b777bbe4040cebc 100644
--- a/media/audio/mac/audio_low_latency_input_mac.cc
+++ b/media/audio/mac/audio_low_latency_input_mac.cc
@@ -195,6 +195,11 @@ bool AUAudioInputStream::Open() {
   }
 
   // Set the desired number of frames in the IO buffer (output scope).
+  // WARNING: Setting this value changes the frame size for all audio units in
+  // the current process.  It's imperative that the input and output frame sizes
+  // be the same as audio_util::GetAudioHardwareBufferSize().
+  // TODO(henrika): Due to http://crrev.com/159666 this is currently not true
+  // and should be fixed, a CHECK() should be added at that time.
   result = AudioUnitSetProperty(audio_unit_,
                                 kAudioDevicePropertyBufferFrameSize,
                                 kAudioUnitScope_Output,