Fix for issue 10488 standalone/basic_debugger_test flaky

runtime/bin/dbg_connection.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_CONNECTION_H_
 #define BIN_DBG_CONNECTION_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 
@@ skipping 79 matching lines @@
   static void RemoveDebuggerConnection(int debug_fd);
   static DebuggerConnectionHandler* GetDebuggerConnectionHandler(int debug_fd);
   static bool IsConnected();
 
   // Helper method for sending messages back to a debugger client.
   static void SendMsgHelper(int debug_fd, dart::TextBuffer* msg);
 
   // mutex/condition variable used by isolates when writing back to the
   // debugger. This is also used to ensure that the isolate waits for
   // a debugger to be attached when that is requested on the command line.
-  static dart::Monitor handler_lock_;
+  static dart::Monitor* handler_lock_;
 
   // The socket that is listening for incoming debugger connections.
   // This descriptor is created and closed by a native thread.
   static int listener_fd_;
 
   friend class DebuggerConnectionImpl;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(DebuggerConnectionHandler);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_DBG_CONNECTION_H_