Implemented HEVC video demuxing and parsing

media/ffmpeg/ffmpeg_common.cc

Index: media/ffmpeg/ffmpeg_common.cc
diff --git a/media/ffmpeg/ffmpeg_common.cc b/media/ffmpeg/ffmpeg_common.cc
index 36d0e7978a84484cc7e86d2f6d49581651fefcbe..5a68ec8822a2924e66455d7fa41c0b6a9c868bcc 100644
--- a/media/ffmpeg/ffmpeg_common.cc
+++ b/media/ffmpeg/ffmpeg_common.cc
@@ -154,6 +154,10 @@ static VideoCodec CodecIDToVideoCodec(AVCodecID codec_id) {
   switch (codec_id) {
     case AV_CODEC_ID_H264:
       return kCodecH264;
+#if defined(ENABLE_HEVC_DEMUXING)
+    case AV_CODEC_ID_HEVC:
+      return kCodecHEVC;
+#endif
     case AV_CODEC_ID_THEORA:
       return kCodecTheora;
     case AV_CODEC_ID_MPEG4:
@@ -172,6 +176,10 @@ static AVCodecID VideoCodecToCodecID(VideoCodec video_codec) {
   switch (video_codec) {
     case kCodecH264:
       return AV_CODEC_ID_H264;
+#if defined(ENABLE_HEVC_DEMUXING)
+    case kCodecHEVC:
+      return AV_CODEC_ID_HEVC;
+#endif
     case kCodecTheora:
       return AV_CODEC_ID_THEORA;
     case kCodecMPEG4: