Make the CancellableSyncSocket non-blocking on Send, and blocking on Receive

content/browser/renderer_host/media/audio_sync_reader.cc

Index: content/browser/renderer_host/media/audio_sync_reader.cc
diff --git a/content/browser/renderer_host/media/audio_sync_reader.cc b/content/browser/renderer_host/media/audio_sync_reader.cc
index 7b6664bbf49f81b8daa41ab455feb50f21a89e93..de121df3fc26dd0c9b65c2010af426b1822655cb 100644
--- a/content/browser/renderer_host/media/audio_sync_reader.cc
+++ b/content/browser/renderer_host/media/audio_sync_reader.cc
@@ -36,7 +36,7 @@ void AudioSyncReader::UpdatePendingBytes(uint32 bytes) {
         shared_memory_,
         media::PacketSizeSizeInBytes(shared_memory_->created_size()));
   }
-  base::AutoLock auto_lock(lock_);
+
   if (socket_.get()) {
     socket_->Send(&bytes, sizeof(bytes));
   }
@@ -84,10 +84,8 @@ uint32 AudioSyncReader::Read(void* data, uint32 size) {
 }
 
 void AudioSyncReader::Close() {
-  base::AutoLock auto_lock(lock_);
   if (socket_.get()) {
     socket_->Close();
-    socket_.reset(NULL);
   }
 }