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

content/browser/renderer_host/media/video_capture_host.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.
 //
 // VideoCaptureHost serves video capture related messages from
 // VideCaptureMessageFilter which lives inside the render process.
 //
 // This class is owned by BrowserRenderProcessHost, and instantiated on UI
 // thread, but all other operations and method calls happen on IO thread.
 //
@@ skipping 60 matching lines @@
   virtual void OnBufferCreated(const VideoCaptureControllerID& id,
                                base::SharedMemoryHandle handle,
                                int length, int buffer_id) OVERRIDE;
   virtual void OnBufferReady(const VideoCaptureControllerID& id,
                              int buffer_id,
                              base::Time timestamp) OVERRIDE;
   virtual void OnFrameInfo(const VideoCaptureControllerID& id,
                            int width,
                            int height,
                            int frame_per_second) OVERRIDE;
+  virtual void OnPaused(const VideoCaptureControllerID& id) OVERRIDE;
   virtual void OnReadyToDelete(const VideoCaptureControllerID& id) OVERRIDE;
 
  private:
   friend class content::BrowserThread;
   friend class base::DeleteHelper<VideoCaptureHost>;
   friend class MockVideoCaptureHost;
   friend class VideoCaptureHostTest;
 
   virtual ~VideoCaptureHost();
 
@@ skipping 39 matching lines @@
   // Send a information about frame resolution and frame rate
   // to the VideoCaptureMessageFilter.
   void DoSendFrameInfo(int device_id,
                        int width,
                        int height,
                        int frame_per_second);
 
   // Handle error coming from VideoCaptureDevice.
   void DoHandleError(int device_id);
 
+  void DoPaused(int device_id);

[mflodman_chromium_OOO, 2012/05/29 09:11:03]

Do we want a comment it should be called on IO-thread?

[wjia(left Chromium), 2012/05/29 16:59:14]

All Do* functions have been renamed to DO*OnIOThread to make it clear that those
functions should be called on IO thread.

[mflodman_chromium_OOO, 2012/05/29 18:19:54]

Nice!

+
   // Helpers.
   media_stream::VideoCaptureManager* GetVideoCaptureManager();
 
   struct Entry;
   typedef std::map<VideoCaptureControllerID, Entry*> EntryMap;
   // A map of VideoCaptureControllerID to its state and VideoCaptureController.
   EntryMap entries_;
 
   // Used to get a pointer to VideoCaptureManager to start/stop capture devices.
   content::ResourceContext* resource_context_;
   media::AudioManager* audio_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureHost);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_HOST_H_