Add a working command line debugger to Observatory.

runtime/observatory/lib/src/app/application.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.
 
 part of app;
 
 /// The observatory application. Instances of this are created and owned
 /// by the observatory_application custom element.
 class ObservatoryApplication extends Observable {
   static ObservatoryApplication app;
@@ skipping 47 matching lines @@
 
     notifications.removeWhere((oldEvent) {
         return (oldEvent.isolate == isolate &&
                 isPauseEvent(oldEvent));
       });
   }
 
   void _onEvent(ServiceEvent event) {
     switch(event.eventType) {
       case 'IsolateCreated':
-        // vm.reload();
+        // Ignore for now.
+        break;
+
+      case 'IsolateResumed':
+        event.isolate.pauseEvent = null;
         break;
 
       case 'IsolateShutdown':
         // TODO(turnidge): Should we show the user isolate shutdown events?
         // What if there are hundreds of them?  Coalesce multiple
         // shutdown events into one notification?
         removePauseEvents(event.isolate);
-        // vm.reload();
+
+        // TODO(turnidge): Reload the isolate for now in case it is
+        // paused.  We may need to distinguish an IsolateShutdown
+        // event from a "paused at isolate shutdown" event.
+        event.isolate.reload();
         break;
 
       case 'BreakpointResolved':
         event.isolate.reloadBreakpoints();
         break;
 
       case 'BreakpointReached':
       case 'IsolateInterrupted':
       case 'ExceptionThrown':
+        event.isolate.pauseEvent = event;
         removePauseEvents(event.isolate);
         notifications.add(event);
         break;
 
       case '_Graph':
         event.isolate.loadHeapSnapshot(event);
         break;
 
       case 'GC':
         // Ignore GC events for now.
@@ skipping 125 matching lines @@
 
   _vmDisconnected(VM vm) {
     if (this.vm != vm) {
       // This disconnect event occured *after* a new VM was installed.
       return;
     }
     this.vm = null;
     notifications.add(new ServiceEvent.vmDisconencted());
   }
 }