Shutdown the sandbox MessageServer before deleting it.

sandbox/mac/message_server.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SANDBOX_MAC_MESSAGE_SERVER_H_
 #define SANDBOX_MAC_MESSAGE_SERVER_H_
 
 #include <mach/mach.h>
 #include <unistd.h>
 
@@ skipping 26 matching lines @@
 // some other technology. This interface is the abstraction on top of those
 // that enables message interception.
 class MessageServer {
  public:
   virtual ~MessageServer() {}
 
   // Initializes the class and starts running the message server. If this
   // returns false, no other methods may be called on this class.
   virtual bool Initialize() = 0;
 
+  // Blocks the calling thread while the server shuts down. This prevents
+  // the server from receiving new messages. After this method is called,
+  // no other methods may be called on this class.
+  virtual void Shutdown() = 0;
+
   // Given a received request message, returns the PID of the sending process.
   virtual pid_t GetMessageSenderPID(IPCMessage request) = 0;
 
   // Creates a reply message from a request message. The result is owned by
   // the server.
   virtual IPCMessage CreateReply(IPCMessage request) = 0;
 
   // Sends a reply message. Returns true if the message was sent successfully.
   virtual bool SendReply(IPCMessage reply) = 0;
 
   // Forwards the original |request| to the |destination| for handling.
   virtual void ForwardMessage(IPCMessage request, mach_port_t destination) = 0;
 
   // Replies to the received |request| message by creating a reply and setting
   // the specified |error_code| in a field that is interpreted by the
   // underlying IPC system.
   virtual void RejectMessage(IPCMessage request, int error_code) = 0;
 
   // Returns the Mach port on which the MessageServer is listening.
   virtual mach_port_t GetServerPort() const = 0;
 };
 
 }  // namespace sandbox
 
 #endif  // SANDBOX_MAC_MESSAGE_SERVER_H_