libvpx: Pull from upstream

source/libvpx/vp9/common/vp9_rtcd.c

 /*
  *  Copyright (c) 2011 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 "./vpx_config.h"
 #define RTCD_C
 #include "./vp9_rtcd.h"
 #include "vpx_ports/vpx_once.h"
 
 void vpx_scale_rtcd(void);
 
 void vp9_rtcd() {
     vpx_scale_rtcd();
+    // TODO(JBB): Remove this once, by insuring that both the encoder and
+    // decoder setup functions are protected by once();
     once(setup_rtcd_internal);
 }