Implement list isolates command

runtime/bin/dbg_message.h

 // Copyright (c) 2012, 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 BIN_DBG_MESSAGE_H_
 #define BIN_DBG_MESSAGE_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 
@@ skipping 227 matching lines @@
                                  intptr_t bp_id,
                                  const Dart_CodeLocation& location);
   static void PausedEventHandler(Dart_IsolateId isolate_id,
                                  const Dart_CodeLocation& loc);
   static void ExceptionThrownHandler(Dart_IsolateId isolate_id,
                                      Dart_Handle exception,
                                      Dart_StackTrace stack_trace);
   static void IsolateEventHandler(Dart_IsolateId isolate_id,
                                   Dart_IsolateEvent kind);
 
+  // Print list of isolate ids of all message queues into text buffer.
+  static void ListIsolateIds(dart::TextBuffer* msg);
+
  private:
   static DbgMsgQueue* GetIsolateMsgQueueLocked(Dart_IsolateId isolate_id);
 
   static DbgMsgQueue* list_;
   static dart::Mutex msg_queue_list_lock_;
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(DbgMsgQueueList);
 };
 
 #endif  // BIN_DBG_MESSAGE_H_