libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_write_bit_buffer.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.
  */
 
+#include <limits.h>
 #include "vp9/encoder/vp9_write_bit_buffer.h"
 
-size_t vp9_rb_bytes_written(struct vp9_write_bit_buffer *wb) {
+size_t vp9_wb_bytes_written(const struct vp9_write_bit_buffer *wb) {
   return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
 }
 
 void vp9_wb_write_bit(struct vp9_write_bit_buffer *wb, int bit) {
   const int off = (int)wb->bit_offset;
   const int p = off / CHAR_BIT;
   const int q = CHAR_BIT - 1 - off % CHAR_BIT;
   if (q == CHAR_BIT -1) {
     wb->bit_buffer[p] = bit << q;
   } else {
     wb->bit_buffer[p] &= ~(1 << q);
     wb->bit_buffer[p] |= bit << q;
   }
   wb->bit_offset = off + 1;
 }
 
 void vp9_wb_write_literal(struct vp9_write_bit_buffer *wb, int data, int bits) {
   int bit;
   for (bit = bits - 1; bit >= 0; bit--)
     vp9_wb_write_bit(wb, (data >> bit) & 1);
 }