vpxdec: normalize frame size types
vpxdec: normalize frame size types

int -> size_t for threshold values. this silences a few signed/unsigned
comparison warnings

Change-Id: Ic7b7af61f75f60a1b6d04167640cea2d09bbd967

shacklettbp/aom,matanbs/vp982,shyamalschandra/libvpx,mbebenita/aom,jdm/libvpx,zofuthan/libvpx,kleopatra999/webm.libvpx,iniwf/webm.libvpx,jdm/libvpx,reimaginemedia/webm.libvpx,gshORTON/webm.libvpx,luctrudeau/aom,shareefalis/libvpx,hsueceumd/test_hui,WebRTC-Labs/libvpx,shareefalis/libvpx,kim42083/webm.libvpx,shyamalschandra/libvpx,charup/https---github.com-webmproject-libvpx-,Laknot/libvpx,reimaginemedia/webm.libvpx,matanbs/webm.libvpx,jacklicn/webm.libvpx,mbebenita/aom,WebRTC-Labs/libvpx,stewnorriss/libvpx,Topopiccione/libvpx,matanbs/vp982,jdm/libvpx,matanbs/webm.libvpx,charup/https---github.com-webmproject-libvpx-,kim42083/webm.libvpx,luctrudeau/aom,iniwf/webm.libvpx,Maria1099/webm.libvpx,reimaginemedia/webm.libvpx,hsueceumd/test_hui,GrokImageCompression/aom,pcwalton/libvpx,pcwalton/libvpx,stewnorriss/libvpx,matanbs/vp982,n4t/libvpx,gshORTON/webm.libvpx,charup/https---github.com-webmproject-libvpx-,shacklettbp/aom,running770/libvpx,liqianggao/libvpx,ittiamvpx/libvpx,jmvalin/aom,matanbs/vp982,shareefalis/libvpx,shacklettbp/aom,ittiamvpx/libvpx-1,Laknot/libvpx,webmproject/libvpx,VTCSecureLLC/libvpx,charup/https---github.com-webmproject-libvpx-,shacklettbp/aom,mwgoldsmith/libvpx,openpeer/libvpx_new,kleopatra999/webm.libvpx,mwgoldsmith/libvpx,Topopiccione/libvpx,shacklettbp/aom,iniwf/webm.libvpx,Laknot/libvpx,kalli123/webm.libvpx,webmproject/libvpx,altogother/webm.libvpx,kleopatra999/webm.libvpx,mbebenita/aom,n4t/libvpx,pcwalton/libvpx,VTCSecureLLC/libvpx,VTCSecureLLC/libvpx,liqianggao/libvpx,matanbs/webm.libvpx,iniwf/webm.libvpx,iniwf/webm.libvpx,hsueceumd/test_hui,ShiftMediaProject/libvpx,luctrudeau/aom,kalli123/webm.libvpx,thdav/aom,pcwalton/libvpx,stewnorriss/libvpx,altogother/webm.libvpx,Distrotech/libvpx,stewnorriss/libvpx,jmvalin/aom,smarter/aom,ittiamvpx/libvpx-1,stewnorriss/libvpx,felipebetancur/libvpx,openpeer/libvpx_new,kleopatra999/webm.libvpx,luctrudeau/aom,reimaginemedia/webm.libvpx,mwgoldsmith/vpx,Distrotech/libvpx,lyx2014/libvpx_c,felipebetancur/libvpx,felipebetancur/libvpx,GrokImageCompression/aom,smarter/aom,kleopatra999/webm.libvpx,matanbs/webm.libvpx,ittiamvpx/libvpx-1,reimaginemedia/webm.libvpx,Topopiccione/libvpx,gshORTON/webm.libvpx,ittiamvpx/libvpx,altogother/webm.libvpx,mwgoldsmith/libvpx,smarter/aom,shareefalis/libvpx,kleopatra999/webm.libvpx,altogother/webm.libvpx,kim42083/webm.libvpx,luctrudeau/aom,hsueceumd/test_hui,liqianggao/libvpx,lyx2014/libvpx_c,smarter/aom,kalli123/webm.libvpx,ittiamvpx/libvpx,mwgoldsmith/libvpx,openpeer/libvpx_new,Maria1099/webm.libvpx,goodleixiao/vpx,mbebenita/aom,ShiftMediaProject/libvpx,WebRTC-Labs/libvpx,luctrudeau/aom,zofuthan/libvpx,abwiz0086/webm.libvpx,WebRTC-Labs/libvpx,jacklicn/webm.libvpx,n4t/libvpx,matanbs/webm.libvpx,kim42083/webm.libvpx,Acidburn0zzz/webm.libvpx,Distrotech/libvpx,n4t/libvpx,matanbs/vp982,lyx2014/libvpx_c,mbebenita/aom,Laknot/libvpx,kalli123/webm.libvpx,pcwalton/libvpx,kalli123/webm.libvpx,shyamalschandra/libvpx,zofuthan/libvpx,running770/libvpx,Acidburn0zzz/webm.libvpx,mwgoldsmith/libvpx,mbebenita/aom,Topopiccione/libvpx,goodleixiao/vpx,zofuthan/libvpx,ittiamvpx/libvpx-1,mbebenita/aom,ittiamvpx/libvpx,gshORTON/webm.libvpx,mwgoldsmith/libvpx,GrokImageCompression/aom,gshORTON/webm.libvpx,webmproject/libvpx,altogother/webm.libvpx,zofuthan/libvpx,pcwalton/libvpx,mbebenita/aom,jacklicn/webm.libvpx,matanbs/vp982,felipebetancur/libvpx,goodleixiao/vpx,shyamalschandra/libvpx,Acidburn0zzz/webm.libvpx,liqianggao/libvpx,Suvarna1488/webm.libvpx,Maria1099/webm.libvpx,felipebetancur/libvpx,thdav/aom,Distrotech/libvpx,hsueceumd/test_hui,mwgoldsmith/vpx,Suvarna1488/webm.libvpx,Maria1099/webm.libvpx,abwiz0086/webm.libvpx,lyx2014/libvpx_c,thdav/aom,jacklicn/webm.libvpx,mwgoldsmith/vpx,Distrotech/libvpx,Laknot/libvpx,thdav/aom,GrokImageCompression/aom,abwiz0086/webm.libvpx,mwgoldsmith/vpx,kalli123/webm.libvpx,stewnorriss/libvpx,jdm/libvpx,matanbs/vp982,Topopiccione/libvpx,ittiamvpx/libvpx-1,jmvalin/aom,openpeer/libvpx_new,kim42083/webm.libvpx,goodleixiao/vpx,VTCSecureLLC/libvpx,Suvarna1488/webm.libvpx,gshORTON/webm.libvpx,Maria1099/webm.libvpx,ittiamvpx/libvpx-1,Acidburn0zzz/webm.libvpx,webmproject/libvpx,abwiz0086/webm.libvpx,Distrotech/libvpx,smarter/aom,running770/libvpx,Acidburn0zzz/webm.libvpx,running770/libvpx,lyx2014/libvpx_c,ShiftMediaProject/libvpx,jacklicn/webm.libvpx,goodleixiao/vpx,thdav/aom,jdm/libvpx,jacklicn/webm.libvpx,zofuthan/libvpx,webmproject/libvpx,openpeer/libvpx_new,ShiftMediaProject/libvpx,altogother/webm.libvpx,shacklettbp/aom,matanbs/webm.libvpx,mwgoldsmith/vpx,VTCSecureLLC/libvpx,mwgoldsmith/vpx,hsueceumd/test_hui,running770/libvpx,lyx2014/libvpx_c,Suvarna1488/webm.libvpx,jmvalin/aom,ittiamvpx/libvpx,iniwf/webm.libvpx,webmproject/libvpx,Laknot/libvpx,shyamalschandra/libvpx,jmvalin/aom,ShiftMediaProject/libvpx,openpeer/libvpx_new,VTCSecureLLC/libvpx,charup/https---github.com-webmproject-libvpx-,shareefalis/libvpx,ittiamvpx/libvpx,WebRTC-Labs/libvpx,thdav/aom,charup/https---github.com-webmproject-libvpx-,goodleixiao/vpx,Suva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