libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_pickmode.c

Index: source/libvpx/vp9/encoder/vp9_pickmode.c
diff --git a/source/libvpx/vp9/encoder/vp9_pickmode.c b/source/libvpx/vp9/encoder/vp9_pickmode.c
index 1af60944f53b8b70521ab31b55384378409c47f2..2c78831832e78cac556630b433a369d0336b297d 100644
--- a/source/libvpx/vp9/encoder/vp9_pickmode.c
+++ b/source/libvpx/vp9/encoder/vp9_pickmode.c
@@ -1058,6 +1058,7 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
                          int mi_row, int mi_col, RD_COST *rd_cost,
                          BLOCK_SIZE bsize, PICK_MODE_CONTEXT *ctx) {
   VP9_COMMON *const cm = &cpi->common;
+  SPEED_FEATURES *const sf = &cpi->sf;
   TileInfo *const tile_info = &tile_data->tile_info;
   MACROBLOCKD *const xd = &x->e_mbd;
   MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
@@ -1217,7 +1218,7 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
       continue;
 
     i = (ref_frame == LAST_FRAME) ? GOLDEN_FRAME : LAST_FRAME;
-    if (cpi->ref_frame_flags & flag_list[i])
+    if ((cpi->ref_frame_flags & flag_list[i]) && sf->reference_masking)
       if (x->pred_mv_sad[ref_frame] > (x->pred_mv_sad[i] << 1))
         ref_frame_skip_mask |= (1 << ref_frame);
     if (ref_frame_skip_mask & (1 << ref_frame))