Remove static mutexes/monitors from dart:io.

runtime/bin/socket.h

 // 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.
 
 #ifndef BIN_SOCKET_H_
 #define BIN_SOCKET_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 
@@ skipping 173 matching lines @@
   static AddressList<InterfaceSocketAddress>* ListInterfaces(
       int type,
       OSError** os_error);
 
   static Dart_Port GetServicePort();
 
   static Dart_Handle SetSocketIdNativeField(Dart_Handle socket, intptr_t id);
   static Dart_Handle GetSocketIdNativeField(Dart_Handle socket, intptr_t* id);
 
  private:
-  static dart::Mutex mutex_;
+  static dart::Mutex* mutex_;
   static int service_ports_size_;
   static Dart_Port* service_ports_;
   static int service_ports_index_;
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Socket);
 };
 
 
 class ServerSocket {
@@ skipping 14 matching lines @@
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(ServerSocket);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_SOCKET_H_