This is the VideoCaptureDevice implementation for windows.

media/video/capture/win/pin_base_win.h

Index: media/video/capture/win/pin_base_win.h
===================================================================
--- media/video/capture/win/pin_base_win.h	(revision 0)
+++ media/video/capture/win/pin_base_win.h	(revision 0)
@@ -0,0 +1,105 @@
+// 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 a DirectShow input pin. It may only be
+// used in a single threaded apartment.
+
+#ifndef MEDIA_VIDEO_CAPTURE_WIN_PIN_BASE_WIN_H_
+#define MEDIA_VIDEO_CAPTURE_WIN_PIN_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"
+
+namespace media {
+
+class PinBase : public IPin,
+                public IMemInputPin,
+                public base::RefCounted<PinBase> {
+ public:
+  explicit PinBase(IBaseFilter* owner);
+  virtual ~PinBase();
+
+  // Checks if a media type is acceptable. This is called when this pin is
+  // connected to an output pin. Must return true if the media type is
+  // acceptable, false otherwise.
+  virtual bool IsMediaTypeValid(const AM_MEDIA_TYPE* media_type) = 0;
+
+  // Enumerates valid media types.
+  virtual bool GetValidMediaType(int index, AM_MEDIA_TYPE* media_type) = 0;
+
+  // Called when new media is received. Note that this is not on the same
+  // thread as where the pin is created.
+  virtual HRESULT STDMETHODCALLTYPE Receive(IMediaSample *pSample) = 0;

[tommi (sloooow) - chröme, 2011/06/23 14:05:56]

follow chromium style (variable naming and position of *) and use STDMETHOD(). 
I.e.

STDMETHOD(Receive)(IMediaSample* sample) = 0;

same for all other COM methods.

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

Done.

+
+  virtual HRESULT STDMETHODCALLTYPE Connect(IPin *pReceivePin,
+                                            const AM_MEDIA_TYPE *pmt);
+
+  virtual HRESULT STDMETHODCALLTYPE ReceiveConnection(
+      IPin *pConnector,
+      const AM_MEDIA_TYPE *pmt);
+
+  virtual HRESULT STDMETHODCALLTYPE Disconnect();
+
+  virtual HRESULT STDMETHODCALLTYPE ConnectedTo(IPin **pPin);
+
+  virtual HRESULT STDMETHODCALLTYPE ConnectionMediaType(AM_MEDIA_TYPE *pmt);
+
+  virtual HRESULT STDMETHODCALLTYPE QueryPinInfo(PIN_INFO *pInfo);
+
+  virtual HRESULT STDMETHODCALLTYPE QueryDirection(PIN_DIRECTION *pPinDir);
+
+  virtual HRESULT STDMETHODCALLTYPE QueryId(LPWSTR *Id);
+
+  virtual HRESULT STDMETHODCALLTYPE QueryAccept(const AM_MEDIA_TYPE *pmt);
+
+  virtual HRESULT STDMETHODCALLTYPE EnumMediaTypes(IEnumMediaTypes **ppEnum);
+
+  virtual HRESULT STDMETHODCALLTYPE QueryInternalConnections(IPin **apPin,
+                                                             ULONG *nPin);
+
+  virtual HRESULT STDMETHODCALLTYPE EndOfStream();
+
+  virtual HRESULT STDMETHODCALLTYPE BeginFlush();
+
+  virtual HRESULT STDMETHODCALLTYPE EndFlush();
+
+  virtual HRESULT STDMETHODCALLTYPE NewSegment(REFERENCE_TIME tStart,
+                                               REFERENCE_TIME tStop,
+                                               double dRate);
+
+  // Inherited from IMemInputPin.
+  virtual HRESULT STDMETHODCALLTYPE GetAllocator(IMemAllocator **ppAllocator);
+
+  virtual HRESULT STDMETHODCALLTYPE NotifyAllocator(IMemAllocator *pAllocator,
+                                                    BOOL bReadOnly);
+
+  virtual HRESULT STDMETHODCALLTYPE GetAllocatorRequirements(
+      ALLOCATOR_PROPERTIES *pProps);
+
+  virtual HRESULT STDMETHODCALLTYPE ReceiveMultiple(IMediaSample **pSamples,
+                                                    long nSamples,
+                                                    long *nSamplesProcessed);
+  virtual HRESULT STDMETHODCALLTYPE ReceiveCanBlock();
+
+  // Inherited from IUnknown.
+  virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID id,
+                                                   void** object_ptr);
+
+  virtual ULONG STDMETHODCALLTYPE AddRef();
+
+  virtual ULONG STDMETHODCALLTYPE Release();
+
+ private:
+  AM_MEDIA_TYPE current_media_type_;
+  IPin* connected_pin_;

[tommi (sloooow) - chröme, 2011/06/23 14:05:56]

ScopedComPtr?

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

Done.

+  IBaseFilter* owner_;

[tommi (sloooow) - chröme, 2011/06/23 14:05:56]

ScopedComPtr?  if not, document why.

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

Done.

+};
+
+}  // namespace media
+
+#endif  // MEDIA_VIDEO_CAPTURE_WIN_PIN_BASE_WIN_H_