Check payload buffer validity. (open-webrtc-toolkit#121)

Merge pull request open-webrtc-toolkit#42 from jianjunz/sei

Don't seek nalu of SEI.

Merge pull request open-webrtc-toolkit#8 from jianjunz/hevc

Add HEVC support for Android.

ICFWX-1682: Published HEVC stream has macroblocks in both mix/forward…

… stream

Change-Id: I082927618aef2eae1cc1ec392158a1173fd4f80c
Reviewed-on: https://git-ccr-1.devtools.intel.com/gerrit/99718
Tested-by: webrtctest <[email protected]>
Reviewed-by: Dai, Jianhui J <[email protected]>
Reviewed-by: Qiu, Jianlin <[email protected]>