Add thread safety to AudioManagerBase to protect access to the audio thread member variable.

This is is a tentative fix for an issue where the AudioManager can crash while tearing down
the audio thread. I suspect that this happens because more than one cleanup attempts were
made since the class wasn't thread safe. I'm also changing direct access to the thread's
MessageLoop* to use MessageLoopProxy based on the same theory.

BUG=110051
TEST=Run media tests.

Review URL: https://chromiumcodereview.appspot.com/9255017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@118272 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 5 insertions, 2 deletions

diff --git a/media/audio/audio_output_proxy.h b/media/audio/audio_output_proxy.h
index af081c1..8e1b350 100644
--- a/media/audio/audio_output_proxy.h
+++ b/media/audio/audio_output_proxy.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -8,6 +8,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
+#include "base/threading/non_thread_safe.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_parameters.h"
 
@@ -21,7 +22,9 @@ class AudioOutputDispatcher;
 //
 // AudioOutputProxy uses AudioOutputDispatcher to open and close
 // physical output streams.
-class MEDIA_EXPORT AudioOutputProxy : public AudioOutputStream {
+class MEDIA_EXPORT AudioOutputProxy
+  : public AudioOutputStream,
+    public NON_EXPORTED_BASE(base::NonThreadSafe) {
  public:
   // Caller keeps ownership of |dispatcher|.
   explicit AudioOutputProxy(AudioOutputDispatcher* dispatcher);