Add support for native ports in the vm.

runtime/vm/native_message_handler.h

Index: runtime/vm/native_message_handler.h
===================================================================
--- runtime/vm/native_message_handler.h	(revision 0)
+++ runtime/vm/native_message_handler.h	(revision 0)
@@ -0,0 +1,47 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_NATIVE_MESSAGE_HANDLER_H_
+#define VM_NATIVE_MESSAGE_HANDLER_H_
+
+#include "include/dart_api.h"
+#include "vm/message.h"
+
+namespace dart {
+
+// A NativeMessageHandler accepts messages and dispatches them to
+// native C handlers.
+class NativeMessageHandler : public MessageHandler {
+ public:
+  NativeMessageHandler(const char* name, Dart_NativeMessageHandler func);
+  ~NativeMessageHandler();
+
+  const char* name() const { return name_; }
+  Dart_NativeMessageHandler func() const { return func_; }
+
+#if defined(DEBUG)
+  // Check that it is safe to access this handler.
+  void CheckAccess();
+#endif
+
+  // Delete this handlers when its last live port is closed.
+  virtual bool OwnedByPortMap() const { return true; }
+
+  // Start a worker thread which will service messages for this handler.
+  //
+  // TODO(turnidge): Instead of starting a worker for each
+  // NativeMessageHandler, we should instead use a shared thread pool
+  // which services a queue of ready MessageHandlers.  If we implement
+  // this correctly, the same pool will work for
+  // IsolateMessageHandlers as well.
+  void StartWorker();
+
+ private:
+  char* name_;
+  Dart_NativeMessageHandler func_;
+};
+
+}  // namespace dart
+
+#endif  // VM_NATIVE_MESSAGE_HANDLER_H_