Update libvpx snapshot to v0.9.7-p1 (Cayuga).

source/libvpx/vp8/decoder/treereader.h

 /*
  *  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 20 matching lines @@
     const vp8_prob *const p
 )
 {
     register vp8_tree_index i = 0;
 
     while ((i = t[ i + vp8_read(r, p[i>>1])]) > 0) ;
 
     return -i;
 }
 
-
-/* Variant reads a binary number given distributions on each bit.
-   Note that tree is arbitrary; probability of decoding a zero
-   may or may not depend on previously decoded bits. */
-
-static int vp8_treed_read_num(
-    vp8_reader *const r,        /* !!! must return a 0 or 1 !!! */
-    vp8_tree t,
-    const vp8_prob *const p
-)
-{
-    vp8_tree_index i = 0;
-    int v = 0, b;
-
-    do
-    {
-        b = vp8_read(r, p[i>>1]);
-        v = (v << 1) + b;
-    }
-    while ((i = t[i+b]) > 0);
-
-    return v;
-}
 #endif /* tree_reader_h */