third_party: Add the libsync library from Android

third_party/libsync/include/linux/sw_sync.h

Index: third_party/libsync/include/linux/sw_sync.h
diff --git a/third_party/libsync/include/linux/sw_sync.h b/third_party/libsync/include/linux/sw_sync.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b5d4869505cb4839cf8875405d337b8b688c5c0
--- /dev/null
+++ b/third_party/libsync/include/linux/sw_sync.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.

[Olof Johansson, 2016/03/02 17:17:21]

Can you import GPLv2 sources in Chromium? I don't think you can, so you probably
need to a clean implementation of this file, right?

[reveman, 2016/03/02 18:00:07]

Right. Latest patch will just have us release these headers under the Apache 2
license.

+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _UAPI_LINUX_SW_SYNC_H
+#define _UAPI_LINUX_SW_SYNC_H
+
+#include <linux/types.h>
+
+struct sw_sync_create_fence_data {
+	__u32	value;
+	char	name[32];
+	__s32	fence; /* fd of new fence */
+};
+
+#define SW_SYNC_IOC_MAGIC	'W'
+
+#define SW_SYNC_IOC_CREATE_FENCE	_IOWR(SW_SYNC_IOC_MAGIC, 0,\
+		struct sw_sync_create_fence_data)
+#define SW_SYNC_IOC_INC			_IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
+
+#endif /* _UAPI_LINUX_SW_SYNC_H */