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 25f6ed4199611e7f7cff332be800d1a3cc9b4238..f06d4dcf92230e672e10d51c86584e830dbd92e7 100644
--- a/media/ffmpeg/ffmpeg_common.cc
+++ b/media/ffmpeg/ffmpeg_common.cc
@@ -153,6 +153,10 @@ 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:
@@ -171,6 +175,10 @@ 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: