Fix incorrect VideoFrame::row_bytes() for RGB. Add tests.

media/base/video_util.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.
 
 #ifndef MEDIA_BASE_VIDEO_UTIL_H_
 #define MEDIA_BASE_VIDEO_UTIL_H_
 
 #include "base/basictypes.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 class VideoFrame;
 
 // Copies a plane of YUV source into a VideoFrame object, taking into account
 // source and destinations dimensions.
 //
 // NOTE: rows is *not* the same as height!
-MEDIA_EXPORT void CopyYPlane(const uint8* source, int stride, int rows,
+MEDIA_EXPORT void CopyYPlane(const uint8* source, size_t stride, size_t rows,
                              VideoFrame* frame);
-MEDIA_EXPORT void CopyUPlane(const uint8* source, int stride, int rows,
+MEDIA_EXPORT void CopyUPlane(const uint8* source, size_t stride, size_t rows,
                              VideoFrame* frame);
-MEDIA_EXPORT void CopyVPlane(const uint8* source, int stride, int rows,
+MEDIA_EXPORT void CopyVPlane(const uint8* source, size_t stride, size_t rows,
                              VideoFrame* frame);
 
 // Fills |frame| containing YUV data to the given color values.
 MEDIA_EXPORT void FillYUV(VideoFrame* frame, uint8 y, uint8 u, uint8 v);
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_UTIL_H_