libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_subexp.c

 /*
  *  Copyright (c) 2013 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 203 matching lines @@
     if (savings > bestsavings) {
       bestsavings = savings;
       bestnewp = newp;
     }
   }
   *bestp = bestnewp;
   return bestsavings;
 }
 
 void vp9_cond_prob_diff_update(vp9_writer *w, vp9_prob *oldp,
-                               vp9_prob upd, unsigned int *ct) {
+                               unsigned int *ct) {
+  const vp9_prob upd = DIFF_UPDATE_PROB;
   vp9_prob newp = get_binary_prob(ct[0], ct[1]);
   const int savings = vp9_prob_diff_update_savings_search(ct, *oldp, &newp,
                                                           upd);
   assert(newp >= 1);
   if (savings > 0) {
     vp9_write(w, 1, upd);
     vp9_write_prob_diff_update(w, newp, *oldp);
     *oldp = newp;
   } else {
     vp9_write(w, 0, upd);
   }
 }