Fix TSAN-detected data race: Sync with audio thread before accessing output_streams_ in unit test c…

media/audio/virtual_audio_input_stream_unittest.cc

Index: media/audio/virtual_audio_input_stream_unittest.cc
diff --git a/media/audio/virtual_audio_input_stream_unittest.cc b/media/audio/virtual_audio_input_stream_unittest.cc
index 93b4b017553fff6eb400541b2cf0904f383457df..5a5be13a599f2935cdade0e30afa2a07eded2778 100644
--- a/media/audio/virtual_audio_input_stream_unittest.cc
+++ b/media/audio/virtual_audio_input_stream_unittest.cc
@@ -161,6 +161,9 @@ class VirtualAudioInputStreamTest
   }
 
   void WaitForDataPulls() {
+    // Wait until audio thread is idle before calling output_streams_.size().
+    SyncWithAudioThread();
+
     const int count = output_streams_.size();
     for (int i = 0; i < count; ++i) {
       source_.WaitForDataPulls();