Add getIsolateID to Service class in dart:developer

sdk/lib/developer/service.dart

 // Copyright (c) 2016, 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.
 
 part of dart.developer;
 
 /// Service protocol is the protocol that a client like the observatory
 /// could use to access the services provided by the Dart VM for
 /// debugging and inspecting Dart programs. This class encapsulates the
 /// version number and Uri for accessing this service.
@@ skipping 55 matching lines @@
     final Completer<Uri> uriCompleter = new Completer<Uri>();
     receivePort.handler = (Uri uri) => uriCompleter.complete(uri);
     // Request the information from the service isolate.
     _webServerControl(receivePort.sendPort, enable);
     // Await the response from the service isolate.
     Uri uri = await uriCompleter.future;
     // Close the port.
     receivePort.close();
     return new ServiceProtocolInfo(uri);
   }
+
+  /// Returns a [String] token representing the ID of [isolate].
+  ///
+  /// Returns null if the running Dart environment does not support the service
+  /// protocol.
+  static String getIsolateID(Isolate isolate) {
+    if (isolate is! Isolate) {
+      throw new ArgumentError.value(isolate,
+                                    'isolate',
+                                    'Must be an Isolate');
+    }
+    return _getIsolateIDFromSendPort(isolate.controlPort);
+  }
 }
 
-/// [sp] will receive a Uri or null.
-external void _getServerInfo(SendPort sp);
+/// [sendPort] will receive a Uri or null.
+external void _getServerInfo(SendPort sendPort);
 
-/// [sp] will receive a Uri or null.
-external void _webServerControl(SendPort sp, bool enable);
+/// [sendPort] will receive a Uri or null.
+external void _webServerControl(SendPort sendPort, bool enable);
 
 /// Returns the major version of the service protocol.
 external int _getServiceMajorVersion();
 
 /// Returns the minor version of the service protocol.
 external int _getServiceMinorVersion();
 
+/// Returns the service id for the isolate that owns [sendPort].
+external String _getIsolateIDFromSendPort(SendPort sendPort);