Changed the API in DartEntry for invoking dart code from C++ to make it more compatible with the re…

vm/custom_isolate_test.cc

 // 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.
 
 #include "include/dart_api.h"
 
 #include "vm/unit_test.h"
 
 // Custom Isolate Test.
 //
@@ skipping 30 matching lines @@
     "    completer.complete(port);\n"
     "    return completer.future;\n"
     "  }\n"
     "\n"
     "  static SendPort _start(entry)\n"
     "      native \"CustomIsolateImpl_start\";\n"
     "\n"
     "  String _entry;\n"
     "}\n"
     "\n"
-    "interface CustomIsolate default CustomIsolateImpl {\n"
-    "  CustomIsolate(String entry);\n"
+    "abstract class CustomIsolate {\n"
+    "  factory CustomIsolate(String entry) = CustomIsolateImpl;\n"
     "\n"
     "  Future<SendPort> spawn();\n"
     "}\n"
     "\n"
     "isolateMain() {\n"
     "   echo('Running isolateMain');\n"
     "   mainPort.receive((message, SendPort replyTo) {\n"
     "     echo('Received: $message');\n"
     "     replyTo.send((message + 1), null);\n"
     "   });\n"
@@ skipping 274 matching lines @@
   OS::Print("-- Finished event loop --\n");
   EXPECT_STREQ("Received: 43", saved_echo);
   free(const_cast<char*>(saved_echo));
 
   delete event_queue;
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart