handle the case when device is closed before media pipeline is fully initialized.

content/browser/renderer_host/media/video_capture_controller.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.
 
 // VideoCaptureController is the glue between VideoCaptureHost,
 // VideoCaptureManager and VideoCaptureDevice.
 // It provides functions for VideoCaptureHost to start a VideoCaptureDevice and
 // is responsible for keeping track of shared DIBs and filling them with I420
 // video frames for IPC communication between VideoCaptureHost and
 // VideoCaptureMessageFilter.
@@ skipping 15 matching lines @@
 #include "content/browser/renderer_host/media/video_capture_controller_event_handler.h"
 #include "content/common/media/video_capture.h"
 #include "media/video/capture/video_capture.h"
 #include "media/video/capture/video_capture_device.h"
 #include "media/video/capture/video_capture_types.h"
 
 namespace media_stream {
 class VideoCaptureManager;
 }  // namespace media_stream
 
-class VideoCaptureController
+class CONTENT_EXPORT VideoCaptureController
     : public base::RefCountedThreadSafe<VideoCaptureController>,
       public media::VideoCaptureDevice::EventHandler {
  public:
   VideoCaptureController(
       media_stream::VideoCaptureManager* video_capture_manager);
 
   // Start video capturing and try to use the resolution specified in
   // |params|.
   // When capturing has started, the |event_handler| receives a call OnFrameInfo
   // with resolution that best matches the requested that the video
@@ skipping 94 matching lines @@
 
   media_stream::VideoCaptureManager* video_capture_manager_;
 
   bool device_in_use_;
   video_capture::State state_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoCaptureController);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_CONTROLLER_H_