Allow Observatory debugger to switch isolates.

runtime/vm/service_event.h

 // Copyright (c) 2015, 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.
 
 #ifndef VM_SERVICE_EVENT_H_
 #define VM_SERVICE_EVENT_H_
 
 #include "vm/debugger.h"
 
 class DebuggerEvent;
 
 namespace dart {
 
 class ServiceEvent {
  public:
   enum EventType {
     kIsolateStart,       // New isolate has started
     kIsolateExit,        // Isolate has exited
+    kIsolateUpdate,      // Isolate identity information has changed
 
     kPauseStart,         // --pause-isolates-on-start
     kPauseExit,          // --pause-isolates-on-exit
     kPauseBreakpoint,
     kPauseInterrupted,
     kPauseException,
     kResume,
 
     kBreakpointAdded,
     kBreakpointResolved,
@@ skipping 53 matching lines @@
   Isolate* isolate_;
   EventType type_;
   SourceBreakpoint* breakpoint_;
   ActivationFrame* top_frame_;
   const Object* exception_;
 };
 
 }  // namespace dart
 
 #endif  // VM_SERVICE_EVENT_H_