libvpx: Add VP9 decoder.

source/libvpx/vp9/common/vp9_modecont.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.
+ */
+
+
+#include "vp9/common/vp9_entropy.h"
+
+const int vp9_default_mode_contexts[INTER_MODE_CONTEXTS][4] = {
+  {223,     1,     1,    237},  // 0,0 best: Only candidate
+  {87,      166,   26,   219},  // 0,0 best: non zero candidates
+  {89,      67,    18,   125},  // 0,0 best: non zero candidates, split
+  {16,      141,   69,   226},  // strong nz candidate(s), no split
+  {35,      122,   14,   227},  // weak nz candidate(s), no split
+  {14,      122,   22,   164},  // strong nz candidate(s), split
+  {16,      70,    9,    183},  // weak nz candidate(s), split
+};