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

media/video/capture/win/video_capture_device_win.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.
 
 // Windows specific implementation of VideoCaptureDevice.
 // DirectShow is used for capturing. DirectShow provide its own threads
 // for capturing.
 
 #ifndef MEDIA_VIDEO_CAPTURE_WIN_VIDEO_CAPTURE_DEVICE_WIN_H_
 #define MEDIA_VIDEO_CAPTURE_WIN_VIDEO_CAPTURE_DEVICE_WIN_H_
@@ skipping 15 matching lines @@
 #include "media/video/capture/win/sink_input_pin_win.h"
 
 namespace media {
 
 // All the methods in the class can only be run on a COM initialized thread.
 class VideoCaptureDeviceWin
     : public base::NonThreadSafe,
       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.
   virtual void AllocateAndStart(
       const VideoCaptureParams& params,
       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.
     kCapturing,  // Video is being captured.
     kError  // Error accessing HW functions.
             // User needs to recover by destroying the object.
   };
 
   // Implements SinkFilterObserver.
   virtual void FrameReceived(const uint8* buffer, int length);
@@ skipping 21 matching lines @@
   // Map of all capabilities this device support.
   CapabilityList capabilities_;
   VideoCaptureFormat capture_format_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoCaptureDeviceWin);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_WIN_VIDEO_CAPTURE_DEVICE_WIN_H_