Move the device enumerate/open/close work to device thread from IO thread

content/browser/renderer_host/media/video_capture_manager.h

Index: content/browser/renderer_host/media/video_capture_manager.h
diff --git a/content/browser/renderer_host/media/video_capture_manager.h b/content/browser/renderer_host/media/video_capture_manager.h
index 1a0628791efe9b369fd879894fe40f2e7d37dcf4..fe164a1099f5e265552e0ab7fa795fe153c2239a 100644
--- a/content/browser/renderer_host/media/video_capture_manager.h
+++ b/content/browser/renderer_host/media/video_capture_manager.h
@@ -15,7 +15,6 @@
 #include <map>
 
 #include "base/memory/ref_counted.h"
-#include "base/threading/thread.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
@@ -30,13 +29,8 @@ class VideoCaptureControllerEventHandler;
 namespace media_stream {
 
 // VideoCaptureManager opens/closes and start/stops video capture devices.
-// It is deleted on the FILE thread so that it can call base::Thread::Stop()
-// there without blocking UI/IO threads. This is also needed for incognito
-// window. When incognito window is closed, IO thread is not in shutdown mode
-// and base::Thread::Stop() can't be called on IO thread.
 class CONTENT_EXPORT VideoCaptureManager
-    : public base::RefCountedThreadSafe<VideoCaptureManager,
-          content::BrowserThread::DeleteOnFileThread>,
+    : public base::RefCountedThreadSafe<VideoCaptureManager>,
       public MediaStreamProvider {
  public:
   // Calling |Start| of this id will open the first device, even though open has
@@ -44,7 +38,8 @@ class CONTENT_EXPORT VideoCaptureManager
   // before MediaStream is implemented in Chrome and WebKit.
   enum { kStartOpenSessionId = 1 };
 
-  VideoCaptureManager();
+  explicit VideoCaptureManager(
+      scoped_refptr<base::MessageLoopProxy> message_loop);
 
   // Implements MediaStreamProvider.
   virtual void Register(MediaStreamProviderListener* listener) OVERRIDE;
@@ -78,7 +73,6 @@ class CONTENT_EXPORT VideoCaptureManager
   // video capture device. Due to timing requirements, the function must be
   // called before EnumerateDevices and Open.
   void UseFakeDevice();
-  MessageLoop* GetMessageLoop();
 
   // Called by VideoCaptureHost to get a controller for |capture_params|.
   // The controller is returned via calling |added_cb|.
@@ -93,11 +87,7 @@ class CONTENT_EXPORT VideoCaptureManager
 
  private:
   friend class ::MockVideoCaptureManager;
-  friend struct content::BrowserThread::DeleteOnThread<
-      content::BrowserThread::FILE>;
-  friend class base::DeleteHelper<VideoCaptureManager>;
-  friend class base::RefCountedThreadSafe<VideoCaptureManager,
-          content::BrowserThread::DeleteOnFileThread>;
+  friend class base::RefCountedThreadSafe<VideoCaptureManager>;
 
   virtual ~VideoCaptureManager();
 
@@ -142,8 +132,8 @@ class CONTENT_EXPORT VideoCaptureManager
   bool IsOnCaptureDeviceThread() const;
   media::VideoCaptureDevice* GetDeviceInternal(int capture_session_id);
 
-  // Thread for all calls to VideoCaptureDevice.
-  base::Thread vc_device_thread_;
+  // The message loop of media stream device thread that this object runs on.
+  scoped_refptr<base::MessageLoopProxy> message_loop_;
 
   // Only accessed on Browser::IO thread.
   MediaStreamProviderListener* listener_;