Disallow UI/IO thread blocking on any other thread.

media/audio/audio_output_controller.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 "media/audio/audio_output_controller.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 
 using base::Time;
 using base::WaitableEvent;
 
 namespace media {
 
 // Signal a pause in low-latency mode.
 const int AudioOutputController::kPauseMark = -1;
 
@@ skipping 13 matching lines @@
       ALLOW_THIS_IN_INITIALIZER_LIST(weak_this_(this)) {
 }
 
 AudioOutputController::~AudioOutputController() {
   DCHECK_EQ(kClosed, state_);
   DCHECK(message_loop_);
 
   if (!message_loop_.get() || message_loop_->BelongsToCurrentThread()) {
     DoStopCloseAndClearStream(NULL);
   } else {
+    // http://crbug.com/120973
+    base::ThreadRestrictions::ScopedAllowWait allow_wait;
     WaitableEvent completion(true /* manual reset */,
                              false /* initial state */);
     message_loop_->PostTask(FROM_HERE,
         base::Bind(&AudioOutputController::DoStopCloseAndClearStream,
                    base::Unretained(this),
                    &completion));
     completion.Wait();
   }
 }
 
@@ skipping 269 matching lines @@
     stream_ = NULL;
     weak_this_.InvalidateWeakPtrs();
   }
 
   // Should be last in the method, do not touch "this" from here on.
   if (done != NULL)
     done->Signal();
 }
 
 }  // namespace media