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

mojo/public/c/system/tests/result_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 result API (the macros declared in
 // mojo/public/c/system/result.h).
 
 #include "mojo/public/c/system/result.h"
+
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 TEST(ResultTest, Macros) {
   EXPECT_EQ(0x12345678u, MOJO_RESULT_MAKE(static_cast<MojoResult>(0x8u),
                                           static_cast<MojoResult>(0x1234u),
                                           static_cast<MojoResult>(0x567u)));
   EXPECT_EQ(0x8u, MOJO_RESULT_GET_CODE(static_cast<MojoResult>(0x12345678u)));
   EXPECT_EQ(0x1234u,
@@ skipping 26 matching lines @@
   EXPECT_EQ(0xbu, MOJO_RESULT_OUT_OF_RANGE);
   EXPECT_EQ(0xcu, MOJO_RESULT_UNIMPLEMENTED);
   EXPECT_EQ(0xdu, MOJO_RESULT_INTERNAL);
   EXPECT_EQ(0xeu, MOJO_RESULT_UNAVAILABLE);
   EXPECT_EQ(0xfu, MOJO_RESULT_DATA_LOSS);
   EXPECT_EQ(0x0019u, MOJO_RESULT_BUSY);
   EXPECT_EQ(0x001eu, MOJO_RESULT_SHOULD_WAIT);
 }
 
 }  // namespace