Fix the continue command.

runtime/observatory/lib/src/elements/debugger.dart

 // Copyright (c) 2014, 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 debugger_page_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'observatory_element.dart';
 import 'package:observatory/app.dart';
@@ skipping 285 matching lines @@
       '\n'
       'Syntax: pause\n';
 }
 
 class ContinueCommand extends DebuggerCommand {
   ContinueCommand(Debugger debugger) : super(debugger, 'continue', []) {
     alias = 'c';
   }
 
   Future run(List<String> args) {
-    debugger.resume();
+    return debugger.resume();
   }
 
   String helpShort = 'Resume execution of the isolate (hotkey: [F7])';
 
   String helpLong =
       'Continue running the isolate.\n'
       '\n'
       'Hotkey: [F7]\n'
       '\n'
       'Syntax: continue\n'
@@ skipping 1982 matching lines @@
         }
       });
   }
 
   void focus() {
     $['textBox'].focus();
   }
 
   DebuggerInputElement.created() : super.created();
 }