[twopass temporal svc] Fix decoding error on seek.
[twopass temporal svc] Fix decoding error on seek.

Don't put small empty frame in front of a key frame. We will
put key frame flag in webm container if there's a visible key
frame. But there will be decoding error when we seek to here
if we put the small empty frame, which will be inter frame,
in front of it.

Change-Id: Id50c2c1fd31da0405ff6faa7375cc2f49c55402d

pcwalton/libvpx,stewnorriss/libvpx,iniwf/webm.libvpx,ShiftMediaProject/libvpx,pcwalton/libvpx,altogother/webm.libvpx,altogother/webm.libvpx,openpeer/libvpx_new,openpeer/libvpx_new,luctrudeau/aom,ittiamvpx/libvpx-1,kim42083/webm.libvpx,jdm/libvpx,GrokImageCompression/aom,luctrudeau/aom,smarter/aom,kim42083/webm.libvpx,Suvarna1488/webm.libvpx,GrokImageCompression/aom,zofuthan/libvpx,reimaginemedia/webm.libvpx,matanbs/webm.libvpx,shacklettbp/aom,matanbs/webm.libvpx,jacklicn/webm.libvpx,mwgoldsmith/vpx,shacklettbp/aom,matanbs/webm.libvpx,VTCSecureLLC/libvpx,kim42083/webm.libvpx,kleopatra999/webm.libvpx,webmproject/libvpx,Maria1099/webm.libvpx,ShiftMediaProject/libvpx,smarter/aom,mbebenita/aom,zofuthan/libvpx,abwiz0086/webm.libvpx,felipebetancur/libvpx,thdav/aom,zofuthan/libvpx,iniwf/webm.libvpx,Acidburn0zzz/webm.libvpx,thdav/aom,Acidburn0zzz/webm.libvpx,kleopatra999/webm.libvpx,Acidburn0zzz/webm.libvpx,abwiz0086/webm.libvpx,shyamalschandra/libvpx,webmproject/libvpx,Distrotech/libvpx,luctrudeau/aom,matanbs/webm.libvpx,Maria1099/webm.libvpx,shareefalis/libvpx,felipebetancur/libvpx,Acidburn0zzz/webm.libvpx,running770/libvpx,pcwalton/libvpx,openpeer/libvpx_new,webmproject/libvpx,shacklettbp/aom,lyx2014/libvpx_c,Topopiccione/libvpx,VTCSecureLLC/libvpx,mbebenita/aom,jacklicn/webm.libvpx,mwgoldsmith/vpx,reimaginemedia/webm.libvpx,Suvarna1488/webm.libvpx,VTCSecureLLC/libvpx,goodleixiao/vpx,running770/libvpx,smarter/aom,mwgoldsmith/vpx,jacklicn/webm.libvpx,ittiamvpx/libvpx-1,gshORTON/webm.libvpx,jdm/libvpx,Topopiccione/libvpx,Acidburn0zzz/webm.libvpx,liqianggao/libvpx,ittiamvpx/libvpx-1,iniwf/webm.libvpx,ShiftMediaProject/libvpx,mwgoldsmith/libvpx,goodleixiao/vpx,smarter/aom,thdav/aom,webmproject/libvpx,Distrotech/libvpx,kalli123/webm.libvpx,Suvarna1488/webm.libvpx,webmproject/libvpx,shacklettbp/aom,stewnorriss/libvpx,abwiz0086/webm.libvpx,jmvalin/aom,kim42083/webm.libvpx,stewnorriss/libvpx,felipebetancur/libvpx,thdav/aom,GrokImageCompression/aom,Topopiccione/libvpx,jmvalin/aom,Distrotech/libvpx,liqianggao/libvpx,Distrotech/libvpx,lyx2014/libvpx_c,altogother/webm.libvpx,lyx2014/libvpx_c,pcwalton/libvpx,kalli123/webm.libvpx,zofuthan/libvpx,reimaginemedia/webm.libvpx,shyamalschandra/libvpx,Maria1099/webm.libvpx,altogother/webm.libvpx,shacklettbp/aom,liqianggao/libvpx,mbebenita/aom,GrokImageCompression/aom,kleopatra999/webm.libvpx,gshORTON/webm.libvpx,goodleixiao/vpx,shyamalschandra/libvpx,mbebenita/aom,jacklicn/webm.libvpx,kleopatra999/webm.libvpx,liqianggao/libvpx,kalli123/webm.libvpx,shareefalis/libvpx,gshORTON/webm.libvpx,mwgoldsmith/vpx,webmproject/libvpx,shyamalschandra/libvpx,shareefalis/libvpx,mwgoldsmith/libvpx,VTCSecureLLC/libvpx,shareefalis/libvpx,mbebenita/aom,mwgoldsmith/libvpx,running770/libvpx,kim42083/webm.libvpx,GrokImageCompression/aom,kleopatra999/webm.libvpx,jdm/libvpx,jacklicn/webm.libvpx,kleopatra999/webm.libvpx,Suvarna1488/webm.libvpx,goodleixiao/vpx,pcwalton/libvpx,jdm/libvpx,Topopiccione/libvpx,ShiftMediaProject/libvpx,jmvalin/aom,iniwf/webm.libvpx,matanbs/webm.libvpx,luctrudeau/aom,gshORTON/webm.libvpx,abwiz0086/webm.libvpx,Distrotech/libvpx,jmvalin/aom,jacklicn/webm.libvpx,goodleixiao/vpx,jdm/libvpx,lyx2014/libvpx_c,altogother/webm.libvpx,pcwalton/libvpx,VTCSecureLLC/libvpx,Suvarna1488/webm.libvpx,lyx2014/libvpx_c,openpeer/libvpx_new,stewnorriss/libvpx,shacklettbp/aom,jmvalin/aom,mwgoldsmith/libvpx,kalli123/webm.libvpx,openpeer/libvpx_new,shyamalschandra/libvpx,ittiamvpx/libvpx-1,goodleixiao/vpx,jmvalin/aom,zofuthan/libvpx,Acidburn0zzz/webm.libvpx,felipebetancur/libvpx,VTCSecureLLC/libvpx,zofuthan/libvpx,kalli123/webm.libvpx,mbebenita/aom,stewnorriss/libvpx,thdav/aom,thdav/aom,jdm/libvpx,mbebenita/aom,running770/libvpx,gshORTON/webm.libvpx,smarter/aom,Maria1099/webm.libvpx,Maria1099/webm.libvpx,iniwf/webm.libvpx,mwgoldsmith/libvpx,stewnorriss/libvpx,abwiz0086/webm.libvpx,liqianggao/libvpx,mbebenita/aom,mwgoldsmith/vpx,felipebetancur/libvpx,shareefalis/libvpx,liqianggao/libvpx,luctrudeau/aom,reimaginemedia/webm.libvpx,smarter/aom,luctrudeau/aom,abwiz0086/webm.libvpx,shareefalis/libvpx,matanbs/webm.libvpx,kim42083/webm.libvpx,ShiftMediaProject/libvpx,reimaginemedia/webm.libvpx,GrokImageCompression/aom,openpeer/libvpx_new,ittiamvpx/libvpx-1,Topopiccione/libvpx,Topopiccione/libvpx,running770/libvpx,felipebetancur/libvpx,altogother/webm.libvpx,Distrotech/libvpx,lyx2014/libvpx_c,shyamalschandra/libvpx,gshORTON/webm.libvpx,reimaginemedia/webm.libvpx,running770/libvpx,iniwf/webm.libvpx,Maria1099/webm.libvpx,kalli123/webm.libvpx,ittiamvpx/libvpx-1,mwgoldsmith/vpx,mwgoldsmith/libvpx,Suvarna1488/webm.libvpx,mbebenita/aom