Reland 10000004 - Make the CancellableSyncSocket non-blocking on Send, and blocking on Receive

content/browser/renderer_host/media/audio_sync_reader.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/media/audio_sync_reader.h"
 
 #include <algorithm>
 
 #include "base/process_util.h"
 #include "base/shared_memory.h"
@@ skipping 18 matching lines @@
 
 // media::AudioOutputController::SyncReader implementations.
 void AudioSyncReader::UpdatePendingBytes(uint32 bytes) {
   if (bytes != static_cast<uint32>(media::AudioOutputController::kPauseMark)) {
     // Store unknown length of data into buffer, so we later
     // can find out if data became available.
     media::SetUnknownDataSize(
         shared_memory_,
         media::PacketSizeSizeInBytes(shared_memory_->created_size()));
   }
-  base::AutoLock auto_lock(lock_);
+
   if (socket_.get()) {
     socket_->Send(&bytes, sizeof(bytes));
   }
 }
 
 uint32 AudioSyncReader::Read(void* data, uint32 size) {
   uint32 max_size = media::PacketSizeSizeInBytes(
       shared_memory_->created_size());
 
 #if defined(OS_WIN)
@@ skipping 27 matching lines @@
   memset(shared_memory_->memory(), 0, max_size);
 
   // Store unknown length of data into buffer, in case renderer does not store
   // the length itself. It also helps in decision if we need to yield.
   media::SetUnknownDataSize(shared_memory_, max_size);
 
   return read_size;
 }
 
 void AudioSyncReader::Close() {
-  base::AutoLock auto_lock(lock_);
   if (socket_.get()) {
     socket_->Close();
-    socket_.reset(NULL);
   }
 }
 
 bool AudioSyncReader::Init() {
   socket_.reset(new base::CancelableSyncSocket());
   foreign_socket_.reset(new base::CancelableSyncSocket());
   return base::CancelableSyncSocket::CreatePair(socket_.get(),
                                                 foreign_socket_.get());
 }
 
@@ skipping 12 matching lines @@
 bool AudioSyncReader::PrepareForeignSocketHandle(
     base::ProcessHandle process_handle,
     base::FileDescriptor* foreign_handle) {
   foreign_handle->fd = foreign_socket_->handle();
   foreign_handle->auto_close = false;
   if (foreign_handle->fd != -1)
     return true;
   return false;
 }
 #endif