Add libvpx thirdparty library

Only necessary files

thirdparty/libvpx/vp8/decoder/decoderthreading.h

@@ -0,0 +1,30 @@
+/*
+ *  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.
+ */
+
+#ifndef VP8_DECODER_DECODERTHREADING_H_
+#define VP8_DECODER_DECODERTHREADING_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if CONFIG_MULTITHREAD
+void vp8mt_decode_mb_rows(VP8D_COMP *pbi, MACROBLOCKD *xd);
+void vp8_decoder_remove_threads(VP8D_COMP *pbi);
+void vp8_decoder_create_threads(VP8D_COMP *pbi);
+void vp8mt_alloc_temp_buffers(VP8D_COMP *pbi, int width, int prev_mb_rows);
+void vp8mt_de_alloc_temp_buffers(VP8D_COMP *pbi, int mb_rows);
+#endif
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // VP8_DECODER_DECODERTHREADING_H_