Add pause/resume for isolates in vmservice/observatory.

runtime/bin/vmservice/client/lib/src/elements/action_link.dart

 // Copyright (c) 2013, 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.
 
-library eval_link_element;
+library action_link_element;
 
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
-@CustomTag('eval-link')
-class EvalLinkElement extends PolymerElement {
-  EvalLinkElement.created() : super.created();
+@CustomTag('action-link')
+class ActionLinkElement extends PolymerElement {
+  ActionLinkElement.created() : super.created();
 
   @observable bool busy = false;
   @published var callback = null;
-  @published String expr = '';
-  @published ServiceObject result = null;
+  @published String label = 'action';
 
-  void evalNow(var a, var b, var c) {
+  void doAction(var a, var b, var c) {
     if (busy) {
       return;
     }
     if (callback != null) {
       busy = true;
-      result = null;
-      callback(expr).then((ServiceObject obj) {
-          result = obj;
-        }).whenComplete(() {
+      // TODO(turnidge): Track down why adding a dummy argument makes
+      // this work but having a no-argument callback doesn't.
+      callback(null).whenComplete(() {
           busy = false;
         });
     }
   }
 }