Revert 96974 - Remove mock_ffmpeg and update media unittests.

media/ffmpeg/ffmpeg_common.cc

 // 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.
 
 #include "media/ffmpeg/ffmpeg_common.h"
 
 #include "base/logging.h"
 
 namespace media {
 
@@ skipping 25 matching lines @@
     case CODEC_ID_VP8:
       return kCodecVP8;
     default:
       NOTREACHED();
   }
   return kUnknown;
 }
 
 CodecID VideoCodecToCodecID(VideoCodec video_codec) {
   switch (video_codec) {
-    case kUnknown:
-      return CODEC_ID_NONE;
     case kCodecVC1:
       return CODEC_ID_VC1;
     case kCodecH264:
       return CODEC_ID_H264;
     case kCodecTheora:
       return CODEC_ID_THEORA;
     case kCodecMPEG2:
       return CODEC_ID_MPEG2VIDEO;
     case kCodecMPEG4:
       return CODEC_ID_MPEG4;
@@ skipping 170 matching lines @@
         avcodec_close(stream->codec);
       }
     }
   }
 
   // Then finally cleanup the format context.
   av_close_input_file(format_context);
 }
 
 }  // namespace media