libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_tokenize.c

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 270 matching lines @@
 
   *tp = t;
 
   vp9_set_contexts(xd, pd, plane_bsize, tx_size, c > 0, aoff, loff);
 }
 
 struct is_skippable_args {
   MACROBLOCK *x;
   int *skippable;
 };
-
 static void is_skippable(int plane, int block,
                          BLOCK_SIZE plane_bsize, TX_SIZE tx_size,
                          void *argv) {
   struct is_skippable_args *args = argv;
   (void)plane_bsize;
   (void)tx_size;
   args->skippable[0] &= (!args->x->plane[plane].eobs[block]);
 }
 
+// TODO(yaowu): rewrite and optimize this function to remove the usage of
+//              vp9_foreach_transform_block() and simplify is_skippable().
 int vp9_is_skippable_in_plane(MACROBLOCK *x, BLOCK_SIZE bsize, int plane) {
   int result = 1;
   struct is_skippable_args args = {x, &result};
   vp9_foreach_transformed_block_in_plane(&x->e_mbd, bsize, plane, is_skippable,
                                          &args);
   return result;
 }
 
 void vp9_tokenize_sb(VP9_COMP *cpi, TOKENEXTRA **t, int dry_run,
                      BLOCK_SIZE bsize) {
@@ skipping 15 matching lines @@
   }
 
   if (!dry_run) {
     cm->counts.skip[ctx][0] += skip_inc;
     vp9_foreach_transformed_block(xd, bsize, tokenize_b, &arg);
   } else {
     vp9_foreach_transformed_block(xd, bsize, set_entropy_context_b, &arg);
     *t = t_backup;
   }
 }