libvpx: Add VP9 decoder.

source/libvpx/libmkv/WebMElement.h

 // Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the LICENSE file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS.  All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 
 
 #ifndef MKV_CONTEXT_HPP
 #define MKV_CONTEXT_HPP 1
 
 void writeSimpleBock(EbmlGlobal *ebml, unsigned char trackNumber, unsigned short timeCode,
                      int isKeyframe, unsigned char lacingFlag, int  discardable,
                      unsigned char *data, unsigned long dataLength);
 
 
 // these are helper functions
 void writeHeader(EbmlGlobal *ebml);
-void writeSegmentInformation(EbmlGlobal *ebml, EbmlLoc* startInfo , unsigned long timeCodeScale, double duration);
-//this function is a helper only, it assumes a lot of defaults
+void writeSegmentInformation(EbmlGlobal *ebml, EbmlLoc *startInfo, unsigned long timeCodeScale, double duration);
+// this function is a helper only, it assumes a lot of defaults
 void writeVideoTrack(EbmlGlobal *ebml, unsigned int trackNumber, int flagLacing,
                      char *codecId, unsigned int pixelWidth, unsigned int pixelHeight,
                      double frameRate);
 void writeAudioTrack(EbmlGlobal *glob, unsigned int trackNumber, int flagLacing,
                      char *codecId, double samplingFrequency, unsigned int channels,
                      unsigned char *private, unsigned long privateSize);
 
 void writeSimpleBlock(EbmlGlobal *ebml, unsigned char trackNumber, short timeCode,
                       int isKeyframe, unsigned char lacingFlag, int discardable,
                       unsigned char *data, unsigned long dataLength);
 
 
 
 #endif