Fix MediaDevices* tests dependency on BrowserThread globals after ~BrowserThreadImpl().

content/browser/renderer_host/media/media_stream_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.
 
 // MediaStreamManager is used to open media capture devices (video supported
 // now). Call flow:
 // 1. GenerateStream is called when a render process wants to use a capture
 //    device.
 // 2. MediaStreamManager will ask MediaStreamUIController for permission to
 //    use devices and for which device to use.
@@ skipping 231 matching lines @@
                             const MediaDeviceInfoArray& devices);
 
   // This method is called when an audio or video device is removed. It makes
   // sure all MediaStreams that use a removed device are stopped and that the
   // render process is notified.
   void StopRemovedDevice(MediaDeviceType type, const MediaDeviceInfo& device);
 
   void SetGenerateStreamCallbackForTesting(
       GenerateStreamTestCallback test_callback);
 
+#if defined(OS_WIN)
+  void FlushVideoCaptureThreadForTesting();
+#endif
+
  private:
   // Contains all data needed to keep track of requests.
   class DeviceRequest;
 
   // |DeviceRequests| is a list to ensure requests are processed in the order
   // they arrive. The first member of the pair is the label of the
   // |DeviceRequest|.
   using LabeledDeviceRequest = std::pair<std::string, DeviceRequest*>;
   using DeviceRequests = std::list<LabeledDeviceRequest>;
 
@@ skipping 141 matching lines @@
   std::map<int, base::Callback<void(const std::string&)>> log_callbacks_;
 
   GenerateStreamTestCallback generate_stream_test_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_MANAGER_H_