ipc: Write end-to-end tests for SharedMemoryHandle brokering on Mac.

ipc/test_util_mac.h

 // Copyright 2015 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.
 
-// This file contains Mac-specific utility functions used by ipc tests.
+// This file contains Mac-specific utility functions used by multiple test
+// suites.
 
 #ifndef IPC_TEST_UTIL_MAC_H_
 #define IPC_TEST_UTIL_MAC_H_
 
 #include <mach/mach.h>
 
 #include <string>
 
 #include "base/mac/scoped_mach_port.h"
 
@@ skipping 19 matching lines @@
 
 // Passes a copy of the send right of |port_to_send| to |receiving_port|, using
 // the given |disposition|.
 void SendMachPort(mach_port_t receiving_port,
                   mach_port_t port_to_send,
                   int disposition);
 
 // The number of active names in the current task's port name space.
 mach_msg_type_number_t GetActiveNameCount();
 
+// The number of references the current task has for a given name.
+mach_port_urefs_t GetMachRefCount(mach_port_name_t name,
+                                  mach_port_right_t right);
+
 // Increments the ref count for the right/name pair.
 void IncrementMachRefCount(mach_port_name_t name, mach_port_right_t right);
 
 }  // namespace IPC
 
 #endif  // IPC_TEST_UTIL_MAC_H_