Add thunks for wait set operations, together with public tests.

mojo/public/c/system/tests/buffer_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file tests the C buffer API (the functions declared in
 // mojo/public/c/system/buffer.h).
 
 #include "mojo/public/c/system/buffer.h"
+
 #include "mojo/public/c/system/handle.h"
 #include "mojo/public/c/system/result.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 const MojoHandleRights kDefaultSharedBufferHandleRights =
     MOJO_HANDLE_RIGHT_DUPLICATE | MOJO_HANDLE_RIGHT_TRANSFER |
     MOJO_HANDLE_RIGHT_GET_OPTIONS | MOJO_HANDLE_RIGHT_SET_OPTIONS |
     MOJO_HANDLE_RIGHT_MAP_READABLE | MOJO_HANDLE_RIGHT_MAP_WRITABLE |
@@ skipping 108 matching lines @@
   EXPECT_EQ(MOJO_RESULT_PERMISSION_DENIED, MojoDuplicateHandle(h2, &h3));
   EXPECT_EQ(MOJO_HANDLE_INVALID, h3);
 
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(h1));
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(h2));
 }
 
 // TODO(vtl): Add multi-threaded tests.
 
 }  // namespace