Always wait for DataReady() on Windows WaveOut.

media/audio/win/waveout_output_win.cc

Index: media/audio/win/waveout_output_win.cc
diff --git a/media/audio/win/waveout_output_win.cc b/media/audio/win/waveout_output_win.cc
index 5e56169a4db67d213a21e086f34777681de1209e..3da5388c13d751e678363b0cda1e58fe05708b5f 100644
--- a/media/audio/win/waveout_output_win.cc
+++ b/media/audio/win/waveout_output_win.cc
@@ -342,6 +342,13 @@ void PCMWaveOutAudioOutputStream::QueueNextPacket(WAVEHDR *buffer) {
   // return to us how many bytes were used.
   // TODO(fbarchard): Handle used 0 by queueing more.
 
+  // HACK: Yield if Read() is called too often.  On older platforms which are
+  // still using the WaveOut back end, we run into synchronization issues where

[scherkus (not reviewing), 2012/11/21 21:37:57]

s/back end/backend/

[DaleCurtis, 2012/11/21 22:42:10]

Done.

+  // the renderer has not finished filling the shared memory when Read() is
+  // called.  Reading too early will lead to clicks and pops.  See issues:
+  // http://crbug.com/161307 and http://crbug.com/61022
+  callback_->WaitTillDataReady();

[DaleCurtis, 2012/11/21 19:31:07]

I'm digging through the WaveOut docs to see if we can just do the equivalent of
"return 0" instead of waiting.

+
   // TODO(sergeyu): Specify correct hardware delay for AudioBuffersState.
   int frames_filled = callback_->OnMoreData(
       audio_bus_.get(), AudioBuffersState(pending_bytes_, 0));