This is the VideoCaptureDevice implementation for windows.

media/video/capture/win/filter_base_win.h

Index: media/video/capture/win/filter_base_win.h
===================================================================
--- media/video/capture/win/filter_base_win.h	(revision 0)
+++ media/video/capture/win/filter_base_win.h	(revision 0)
@@ -0,0 +1,72 @@
+// Copyright (c) 2011 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.
+
+// Implement a simple base class for DirectShow filters. It may only be used in
+// a single threaded apartment.
+
+#ifndef MEDIA_VIDEO_CAPTURE_WIN_FILTER_BASE_WIN_H_
+#define MEDIA_VIDEO_CAPTURE_WIN_FILTER_BASE_WIN_H_
+#pragma once
+
+// Avoid including strsafe.h via dshow as it will cause build warnings.
+#define NO_DSHOW_STRSAFE
+#include <dshow.h>
+
+#include "base/memory/ref_counted.h"
+#include "base/win/scoped_comptr.h"
+
+namespace media {
+
+class FilterBase : public IBaseFilter,

[scherkus (not reviewing), 2011/06/24 20:15:26]

nit: style should be same as initializer list (drop to next line, 4 space
indent, etc.)

[Per K, 2011/06/27 11:47:50]

Done.

+                   public base::RefCounted<FilterBase> {
+ public:
+  FilterBase();
+  virtual ~FilterBase();
+
+  // Number of pins connected to this filter.
+  virtual int NoOfPins() = 0;
+  // Returns the IPin interface pin no index.
+  virtual IPin* GetPin(int index) = 0;
+
+  // Inherited from IUnknown.
+  STDMETHOD(QueryInterface)(REFIID id, void** object_ptr);
+  STDMETHOD_(ULONG, AddRef)();
+  STDMETHOD_(ULONG, Release)();
+
+  // Inherited from IBaseFilter.
+  STDMETHOD(EnumPins)(IEnumPins** enum_pins);
+
+  STDMETHOD(FindPin)(LPCWSTR id, IPin** pin);
+
+  STDMETHOD(QueryFilterInfo)(FILTER_INFO* info);
+
+  STDMETHOD(JoinFilterGraph)(IFilterGraph* graph, LPCWSTR name);
+
+  STDMETHOD(QueryVendorInfo)(LPWSTR* vendor_info);
+
+  // Inherited from IMediaFilter.
+  STDMETHOD(Stop)();
+
+  STDMETHOD(Pause)();
+
+  STDMETHOD(Run)(REFERENCE_TIME start);
+
+  STDMETHOD(GetState)(DWORD msec_timeout, FILTER_STATE* state);
+
+  STDMETHOD(SetSyncSource)(IReferenceClock* clock);
+
+  STDMETHOD(GetSyncSource)(IReferenceClock** clock);
+
+  // Inherited from IPersistent.
+  STDMETHOD(GetClassID)(CLSID* class_id) = 0;
+
+ private:
+  FILTER_STATE state_;
+  base::win::ScopedComPtr<IFilterGraph> owning_graph_;
+  int ref_count_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_VIDEO_CAPTURE_WIN_FILTER_BASE_WIN_H_