Move mojo::{Wait,WaitMany}() to (the newly-added) mojo/public/cpp/system/wait.h.

mojo/public/platform/dart/mojo_natives.cc

 // Copyright 2014 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.
 
 #include <stdio.h>
 #include <string.h>
 
 #include <memory>
 #include <vector>
 
 #include "dart/runtime/include/dart_api.h"
 #include "mojo/public/c/system/buffer.h"
 #include "mojo/public/c/system/data_pipe.h"
 #include "mojo/public/c/system/handle.h"
 #include "mojo/public/c/system/message_pipe.h"
 #include "mojo/public/c/system/result.h"
 #include "mojo/public/c/system/time.h"
 #include "mojo/public/cpp/environment/logging.h"
 #include "mojo/public/cpp/system/core.h"
 #include "mojo/public/cpp/system/macros.h"
+#include "mojo/public/cpp/system/wait.h"
 #include "mojo/public/platform/dart/dart_handle_watcher.h"
 
 namespace mojo {
 namespace dart {
 
 #define REGISTER_FUNCTION(name, count)                                         \
   { "" #name, name, count },
 #define DECLARE_FUNCTION(name, count)                                          \
   extern void name(Dart_NativeArguments args);
 
@@ skipping 813 matching lines @@
       reinterpret_cast<const void*>(&command),
       sizeof(command),
       nullptr,
       0,
       0);
   Dart_SetIntegerReturnValue(arguments, static_cast<int64_t>(res));
 }
 
 }  // namespace dart
 }  // namespace mojo