libvpx: Add VP9 decoder.

source/libvpx/vp9/common/vp9_mvref_common.h

+/*
+ *  Copyright (c) 2012 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_onyxc_int.h"
+#include "vp9/common/vp9_blockd.h"
+
+
+#ifndef VP9_COMMON_VP9_MVREF_COMMON_H_
+#define VP9_COMMON_VP9_MVREF_COMMON_H_
+
+void vp9_find_mv_refs(
+  MACROBLOCKD *xd,
+  MODE_INFO *here,
+  MODE_INFO *lf_here,
+  MV_REFERENCE_FRAME ref_frame,
+  int_mv * mv_ref_list,
+  int *ref_sign_bias
+);
+
+#endif
+