Revert "Multithreaded encoder, late sync loopfilter"
Revert "Multithreaded encoder, late sync loopfilter"

This commit is incomplete, as it does not synchronize the loop filter
before returning a handle to the reconstructed frame in
vpx_codec_get_preview_frame(), which can cause (false?) failures
when running the test_reconstruct_buffer test.

This may be related to a bug that does cause visible artifacts, which
is also under investigation.

This reverts commit 380d64ecb19984a1466e727244a41445ae919060.

Change-Id: Iad710941e7731d44fc2bde63bc63d6763cc4629e

awatry/libvpx.opencl,gshORTON/webm.libvpx,running770/libvpx,openpeer/libvpx_new,charup/https---github.com-webmproject-libvpx-,jdm/libvpx,ittiamvpx/libvpx,VTCSecureLLC/libvpx,Suvarna1488/webm.libvpx,thdav/aom,mbebenita/aom,WebRTC-Labs/libvpx,altogother/webm.libvpx,Acidburn0zzz/webm.libvpx,abwiz0086/webm.libvpx,jacklicn/webm.libvpx,thdav/aom,iniwf/webm.libvpx,running770/libvpx,mwgoldsmith/libvpx,kalli123/webm.libvpx,pcwalton/libvpx,kalli123/webm.libvpx,goodleixiao/vpx,VTCSecureLLC/libvpx,openpeer/libvpx_new,turbulenz/libvpx,VTCSecureLLC/libvpx,lyx2014/libvpx_c,vasilvv/esvp8,shyamalschandra/libvpx,ittiamvpx/libvpx-1,n4t/libvpx,turbulenz/libvpx,felipebetancur/libvpx,zofuthan/libvpx,webmproject/libvpx,shareefalis/libvpx,stewnorriss/libvpx,Maria1099/webm.libvpx,turbulenz/libvpx,matanbs/vp982,turbulenz/libvpx,lyx2014/libvpx_c,Topopiccione/libvpx,GrokImageCompression/aom,pcwalton/libvpx,shyamalschandra/libvpx,jmvalin/aom,gshORTON/webm.libvpx,openpeer/libvpx_new,zofuthan/libvpx,smarter/aom,awatry/libvpx.opencl,sanyaade-teachings/libvpx,shacklettbp/aom,zofuthan/libvpx,ittiamvpx/libvpx,iniwf/webm.libvpx,shareefalis/libvpx,VTCSecureLLC/libvpx,cinema6/libvpx,goodleixiao/vpx,n4t/libvpx,goodleixiao/vpx,Acidburn0zzz/webm.libvpx,matanbs/vp982,matanbs/vp982,gshORTON/webm.libvpx,altogother/webm.libvpx,ittiamvpx/libvpx,zofuthan/libvpx,mbebenita/aom,jacklicn/webm.libvpx,n4t/libvpx,WebRTC-Labs/libvpx,webmproject/libvpx,ittiamvpx/libvpx,stewnorriss/libvpx,felipebetancur/libvpx,awatry/libvpx.opencl,jmvalin/aom,cinema6/libvpx,jdm/libvpx,luctrudeau/aom,luctrudeau/aom,cinema6/libvpx,kim42083/webm.libvpx,luctrudeau/aom,jdm/libvpx,WebRTC-Labs/libvpx,smarter/aom,shareefalis/libvpx,cinema6/libvpx,liqianggao/libvpx,charup/https---github.com-webmproject-libvpx-,charup/https---github.com-webmproject-libvpx-,lyx2014/libvpx_c,sanyaade-teachings/libvpx,hsueceumd/test_hui,lyx2014/libvpx_c,Topopiccione/libvpx,shareefalis/libvpx,shacklettbp/aom,mbebenita/aom,turbulenz/libvpx,kim42083/webm.libvpx,Suvarna1488/webm.libvpx,ShiftMediaProject/libvpx,charup/https---github.com-webmproject-libvpx-,reimaginemedia/webm.libvpx,smarter/aom,reimaginemedia/webm.libvpx,jacklicn/webm.libvpx,mbebenita/aom,luctrudeau/aom,n4t/libvpx,stewnorriss/libvpx,shyamalschandra/libvpx,jmvalin/aom,goodleixiao/vpx,Acidburn0zzz/webm.libvpx,shacklettbp/aom,charup/https---github.com-webmproject-libvpx-,ittiamvpx/libvpx-1,abwiz0086/webm.libvpx,Suvarna1488/webm.libvpx,hsueceumd/test_hui,kleopatra999/webm.libvpx,gshORTON/webm.libvpx,Distrotech/libvpx,matanbs/vp982,felipebetancur/libvpx,Distrotech/libvpx,ittiamvpx/libvpx,kleopatra999/webm.libvpx,Maria1099/webm.libvpx,shacklettbp/aom,zofuthan/libvpx,kim42083/webm.libvpx,webmproject/libvpx,Suvarna1488/webm.libvpx,abwiz0086/webm.libvpx,turbulenz/libvpx,iniwf/webm.libvpx,pcwalton/libvpx,mwgoldsmith/vpx,reimaginemedia/webm.libvpx,thdav/aom,VTCSecureLLC/libvpx,vasilvv/esvp8,jdm/libvpx,goodleixiao/vpx,Laknot/libvpx,jacklicn/webm.libvpx,abwiz0086/webm.libvpx,VTCSecureLLC/libvpx,vasilvv/esvp8,jacklicn/webm.libvpx,thdav/aom,sanyaade-teachings/libvpx,mwgoldsmith/vpx,Suvarna1488/webm.libvpx,Topopiccione/libvpx,openpeer/libvpx_new,liqianggao/libvpx,mwgoldsmith/libvpx,Laknot/libvpx,ittiamvpx/libvpx-1,smarter/aom,vasilvv/esvp8,reimaginemedia/webm.libvpx,altogother/webm.libvpx,reimaginemedia/webm.libvpx,charup/https---github.com-webmproject-libvpx-,running770/libvpx,matanbs/webm.libvpx,Acidburn0zzz/webm.libvpx,matanbs/vp982,mwgoldsmith/libvpx,hsueceumd/test_hui,kim42083/webm.libvpx,WebRTC-Labs/libvpx,mbebenita/aom,n4t/libvpx,vasilvv/esvp8,mwgoldsmith/libvpx,Suvarna1488/webm.libvpx,Laknot/libvpx,kim42083/webm.libvpx,zofuthan/libvpx,Laknot/libvpx,kalli123/webm.libvpx,Maria1099/webm.libvpx,ittiamvpx/libvpx-1,mbebenita/aom,vasilvv/esvp8,openpeer/libvpx_new,Maria1099/webm.libvpx,matanbs/webm.libvpx,kleopatra999/webm.libvpx,sanyaade-teachings/libvpx,jmvalin/aom,pcwalton/libvpx,kleopatra999/webm.libvpx,matanbs/webm.libvpx,GrokImageCompression/aom,mwgoldsmith/vpx,GrokImageCompression/aom,running770/libvpx,GrokImageCompression/aom,liqianggao/libvpx,kleopatra999/webm.libvpx,matanbs/webm.libvpx,thdav/aom,turbulenz/libvpx,Laknot/libvpx,WebRTC-Labs/libvpx,Topopiccione/libvpx,stewnorriss/libvpx,jacklicn/webm.libvpx,Distrotech/libvpx,matanbs/vp982,pcwalton/libvpx,ittiamvpx/libvpx,altogother/webm.libvpx,kalli123/webm.libvpx,lyx2014/libvpx_c,stewnorriss/libvpx,ShiftMediaProject/libvpx,shacklettbp/aom,ShiftMediaProject/libvpx,cinema6/libvpx,reimaginemedia/webm.libvpx,kim42083/webm.libvpx,felipebetancur/libvpx,felipebetancur/libvpx,shacklettbp/aom,thdav/aom,stewnorriss/libvpx,Maria1099/webm.libvpx,mwgoldsmith/vpx,cinema6/libvpx,mwgoldsmith/libvpx,matanbs/webm.libvpx,jdm/libvpx,shareefalis/libvpx,kleopatra999/webm.libvpx,Acidburn0zzz/webm.libvpx,abwiz0086/webm.libvpx,GrokImageCompression/aom,Acidburn0zzz/webm.libvpx,Topopiccione/libvpx,mbebenita/aom,webmproject/libvpx,hsueceumd/test_hui,kalli123/webm.libvpx,liqianggao/libvpx,ShiftMediaProject/libvpx,pcwalton/libvpx,iniwf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