Fix race when setting Desktop window id.

content/browser/renderer_host/media/video_capture_manager.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.
 
 // VideoCaptureManager is used to open/close, start/stop, enumerate available
 // video capture devices, and manage VideoCaptureController's.
 // All functions are expected to be called from Browser::IO thread. Some helper
 // functions (*OnDeviceThread) will dispatch operations to the device thread.
 // VideoCaptureManager will open OS dependent instances of VideoCaptureDevice.
 // A device can only be opened once.
@@ skipping 205 matching lines @@
       scoped_ptr<media::VideoCaptureDevice::Client> client);
 
   // Stops and destroys the VideoCaptureDevice held in
   // |device|.
   void DoStopDeviceOnDeviceThread(scoped_ptr<media::VideoCaptureDevice> device);
 
   media::VideoCaptureDeviceInfo* FindDeviceInfoById(
       const std::string& id,
       media::VideoCaptureDeviceInfos& device_vector);
 
+  void MaybePostDesktopCaptureWindowId(media::VideoCaptureSessionId session_id);
   void SetDesktopCaptureWindowIdOnDeviceThread(
       media::VideoCaptureDevice* device,
       gfx::NativeViewId window_id);
 
-  void SaveDesktopCaptureWindowIdOnDeviceThread(
-      media::VideoCaptureSessionId session_id,
-      gfx::NativeViewId window_id);
-
   // The message loop of media stream device thread, where VCD's live.
   scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
 
   // Only accessed on Browser::IO thread.
   MediaStreamProviderListener* listener_;
   media::VideoCaptureSessionId new_capture_session_id_;
 
   typedef std::map<media::VideoCaptureSessionId, MediaStreamDevice> SessionMap;
   // An entry is kept in this map for every session that has been created via
   // the Open() entry point. The keys are session_id's. This map is used to
@@ skipping 73 matching lines @@
 
   // Local cache of the enumerated video capture devices' names and capture
   // supported formats. A snapshot of the current devices and their capabilities
   // is composed in VideoCaptureDeviceFactory::EnumerateDeviceNames() and
   // ConsolidateDevicesInfoOnDeviceThread(), and this snapshot is used to update
   // this list in OnDevicesInfoEnumerated(). GetDeviceSupportedFormats() will
   // use this list if the device is not started, otherwise it will retrieve the
   // active device capture format from the VideoCaptureController associated.
   media::VideoCaptureDeviceInfos devices_info_cache_;
 
-  // Accessed on the device thread only.
+  // Map used by DesktopCapture.
   std::map<media::VideoCaptureSessionId, gfx::NativeViewId>
       notification_window_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_