There is a racing between SyncSocket::Receive in audio_thread_ and SyncSocket::Close in renderer ...

content/renderer/media/audio_input_device.h

 // Copyright (c) 2011 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 196 matching lines @@
   int32 stream_id_;
 
   // The media session ID used to identify which input device to be started.
   // Only modified on the IO thread.
   int session_id_;
 
   // State variable used to indicate it is waiting for a OnDeviceReady()
   // callback. Only modified on the IO thread.
   bool pending_device_ready_;
 
+  // WaitableEvent for signaling the audio thread that it should stop.
+  base::WaitableEvent audio_event_;
+
   scoped_ptr<base::SharedMemory> shared_memory_;
   scoped_ptr<base::SyncSocket> socket_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AudioInputDevice);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_INPUT_DEVICE_H_