Monitor the IO message loop in the AudioDevice classes.

content/renderer/media/audio_input_device.h

 // 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.
 
 // Low-latency audio capturing unit utilizing audio input stream provided
 // by browser process through IPC.
 //
 // Relationship of classes:
 //
 //  AudioInputController                 AudioInputDevice
@@ skipping 60 matching lines @@
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/shared_memory.h"
 #include "base/threading/simple_thread.h"
 #include "content/common/content_export.h"
 #include "content/renderer/media/audio_input_message_filter.h"
+#include "content/renderer/media/scoped_loop_observer.h"
 #include "media/audio/audio_parameters.h"
 
 // TODO(henrika): This class is based on the AudioDevice class and it has
 // many components in common. Investigate potential for re-factoring.
 // TODO(henrika): Add support for event handling (e.g. OnStateChanged,
 // OnCaptureStopped etc.) and ensure that we can deliver these notifications
 // to any clients using this class.
 class CONTENT_EXPORT AudioInputDevice
     : public AudioInputMessageFilter::Delegate,
       public base::DelegateSimpleThread::Delegate,
+      public ScopedLoopObserver,
       public base::RefCountedThreadSafe<AudioInputDevice> {
  public:
   class CONTENT_EXPORT CaptureCallback {
    public:
     virtual void Capture(const std::vector<float*>& audio_data,
                          size_t number_of_frames,
                          size_t audio_delay_milliseconds) = 0;
    protected:
     virtual ~CaptureCallback() {}
   };
@@ skipping 68 matching lines @@
 
   void Send(IPC::Message* message);
 
   // Method called on the audio thread ----------------------------------------
   // Calls the client's callback for capturing audio.
   void FireCaptureCallback(int16* input_audio);
 
   // DelegateSimpleThread::Delegate implementation.
   virtual void Run() OVERRIDE;
 
+  // MessageLoop::DestructionObserver implementation for the IO loop.
+  // If the IO loop dies before we do, we shut down the audio thread from here.
+  virtual void WillDestroyCurrentMessageLoop() OVERRIDE;
+
   // Format
   AudioParameters audio_parameters_;
 
   CaptureCallback* callback_;
   CaptureEventHandler* event_handler_;
 
   // The client callback receives captured audio here.
   std::vector<float*> audio_data_;
 
   // The client stores the last reported audio delay in this member.
@@ skipping 22 matching lines @@
   bool pending_device_ready_;
 
   base::SharedMemoryHandle shared_memory_handle_;
   scoped_ptr<base::CancelableSyncSocket> audio_socket_;
   int memory_length_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AudioInputDevice);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_INPUT_DEVICE_H_