Video capture: Refactor GetBestMatchedFormat from Win to OS independent

media/video/capture/win/capability_list_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_CAPABILITY_LIST_WIN_H_
 #define MEDIA_VIDEO_CAPTURE_WIN_CAPABILITY_LIST_WIN_H_
 
 #include <list>
+#include <utility>
 
 #include "base/basictypes.h"
 #include "base/threading/non_thread_safe.h"
 #include "media/video/capture/video_capture_types.h"
 
 namespace media {
 
-struct VideoCaptureCapabilityWin {
-  explicit VideoCaptureCapabilityWin(int index)
-      : stream_index(index),
-        frame_rate_numerator(0),
-        frame_rate_denominator(1) {}
-  int stream_index;
-  // Internally to Media Foundation Api type devices we use rational framerates
-  // so framerates can be properly represented, f.i. 29.971fps= 30000/1001.
-  int frame_rate_numerator;
-  int frame_rate_denominator;
-  VideoCaptureFormat supported_format;
-};
+typedef std::pair<int, VideoCaptureFormat> VideoCaptureCapabilityWin;
+typedef std::list<VideoCaptureCapabilityWin> CapabilityList;
 
-class CapabilityList : public base::NonThreadSafe {
- public:
-  CapabilityList();
-  ~CapabilityList();
-
-  bool empty() const { return capabilities_.empty(); }
-
-  // Appends an entry to the list.
-  void Add(const VideoCaptureCapabilityWin& capability);
-
-  // Loops through the list of capabilities and returns an index of the best
-  // matching capability.  The algorithm prioritizes height, width, frame rate
-  // and color format in that order.
-  const VideoCaptureCapabilityWin& GetBestMatchedFormat(
-      int requested_width,
-      int requested_height,
-      float requested_frame_rate) const;
-
- private:
-  typedef std::list<VideoCaptureCapabilityWin> Capabilities;
-  Capabilities capabilities_;
-
-  DISALLOW_COPY_AND_ASSIGN(CapabilityList);
-};
+CapabilityList::const_iterator GetBestMatchedFormat(
+    const VideoCaptureFormat& requested,
+    const CapabilityList& capabilities);
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_WIN_CAPABILITY_LIST_WIN_H_