VideoCaptureDeviceWin: Extract class-static method into a Factory (both MF/DS)

media/video/capture/win/video_capture_device_win.h

Index: media/video/capture/win/video_capture_device_win.h
diff --git a/media/video/capture/win/video_capture_device_win.h b/media/video/capture/win/video_capture_device_win.h
index ac4b704f4e6d7d076169a5d4a1ad762a7102e831..5ab9faaca0599014938d466020d239eae89f138e 100644
--- a/media/video/capture/win/video_capture_device_win.h
+++ b/media/video/capture/win/video_capture_device_win.h
@@ -33,10 +33,38 @@ class VideoCaptureDeviceWin
       public VideoCaptureDevice,
       public SinkFilterObserver {
  public:
+  // A utility class that wraps the AM_MEDIA_TYPE type and guarantees that
+  // we free the structure when exiting the scope.  DCHECKing is also done to
+  // avoid memory leaks.
+  class ScopedMediaType {
+   public:
+    ScopedMediaType() : media_type_(NULL) {}
+    ~ScopedMediaType() { Free(); }
+
+    AM_MEDIA_TYPE* operator->() { return media_type_; }
+    AM_MEDIA_TYPE* get() { return media_type_; }
+    void Free();
+    AM_MEDIA_TYPE** Receive();
+
+   private:
+    void FreeMediaType(AM_MEDIA_TYPE* mt);
+    void DeleteMediaType(AM_MEDIA_TYPE* mt);
+
+    AM_MEDIA_TYPE* media_type_;
+  };
+
+  static HRESULT GetDeviceFilter(const Name& device_name,
+                                 IBaseFilter** filter);
+  static bool PinMatchesCategory(IPin* pin, REFGUID category);
+  static base::win::ScopedComPtr<IPin> GetPin(IBaseFilter* filter,
+                                              PIN_DIRECTION pin_dir,
+                                              REFGUID category);
+  static VideoPixelFormat TranslateMediaSubtypeToPixelFormat(
+      const GUID& sub_type);
+
   explicit VideoCaptureDeviceWin(const Name& device_name);
   virtual ~VideoCaptureDeviceWin();
   // Opens the device driver for this device.
-  // This function is used by the static VideoCaptureDevice::Create function.
   bool Init();
 
   // VideoCaptureDevice implementation.
@@ -45,10 +73,6 @@ class VideoCaptureDeviceWin
       scoped_ptr<VideoCaptureDevice::Client> client) OVERRIDE;
   virtual void StopAndDeAllocate() OVERRIDE;
 
-  static void GetDeviceNames(Names* device_names);
-  static void GetDeviceSupportedFormats(const Name& device,
-                                        VideoCaptureFormats* formats);
-
  private:
   enum InternalState {
     kIdle,  // The device driver is opened but camera is not in use.