Add a mid-sized integration test for the Dart Embedding Api which

runtime/vm/port.h

 // Copyright (c) 2011, 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_PORT_H_
 #define VM_PORT_H_
 
 #include "include/dart_api.h"
 #include "vm/allocation.h"
 #include "vm/globals.h"
 
 namespace dart {
 
 class Isolate;
 class Mutex;
+class PortMapTestPeer;
 
 class PortMap: public AllStatic {
  public:
   // Allocate a port in the current isolate and return its VM-global id.
   static Dart_Port CreatePort();
 
+  // Indicates that a port has had a ReceivePort created for it at the
+  // dart language level.  The port remains live until it is closed.
+  static void SetLive(Dart_Port id);
+
   // Close the port with id. All pending messages will be dropped.
   static void ClosePort(Dart_Port id);
 
   // Close all the ports of the current isolate.
   static void ClosePorts();
 
-  static bool IsActivePort(Dart_Port id);
-
   // Enqueues the message in the port with id. Returns false if the port is not
   // active any longer.
   //
   // Claims ownership of the memory pointed to by 'message' and will
   // ensure that free(message) is called.
   static bool PostMessage(Dart_Port dest_port,
                           Dart_Port reply_port,
                           Dart_Message message);
 
   static void InitOnce();
 
  private:
+  friend class dart::PortMapTestPeer;
+
   // Mapping between port numbers and isolates.
   // Free entries have id == 0 and isolate == NULL. Deleted entries have id == 0
   // and isolate == deleted_entry_.
   typedef struct {
     Dart_Port port;
     Isolate* isolate;
+    bool live;
   } Entry;
 
   // Allocate a new unique port.
   static Dart_Port AllocatePort();
 
+  static bool IsActivePort(Dart_Port id);
+  static bool IsLivePort(Dart_Port id);
+
   static intptr_t FindPort(Dart_Port port);
   static void Rehash(intptr_t new_capacity);
 
   static void MaintainInvariants();
 
   // Lock protecting access to the port map.
   static Mutex* mutex_;
 
   // Hashmap of ports.
   static Entry* map_;
   static Isolate* deleted_entry_;
   static intptr_t capacity_;
   static intptr_t used_;
   static intptr_t deleted_;
 
   static Dart_Port next_port_;
 };
 
 }  // namespace dart
 
 #endif  // VM_PORT_H_