Refactor init_gop_frame()
Refactor init_gop_frame()

Remove implicit dependency on overlay frame update to break the
gop initialization loop.

Change-Id: I6a6d070cdf22a0e30c298523707bd746fd03f450

ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx