[Mac] Add a perf test that counts the number of Mach ports in the browser.

base/mach_ipc_mac.h

 // Copyright (c) 2011 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 BASE_MACH_IPC_MAC_H_
 #define BASE_MACH_IPC_MAC_H_
 #pragma once
 
 #include <mach/mach.h>
 #include <mach/message.h>
@@ skipping 291 matching lines @@
   kern_return_t SendMessage(MachSendMessage &message,
                             mach_msg_timeout_t timeout);
 
  private:
   mach_port_t   send_port_;
   kern_return_t init_result_;
 
   DISALLOW_COPY_AND_ASSIGN(MachPortSender);
 };
 
+//==============================================================================
+// Static utility functions.
+
+namespace mac {
+
+// Returns the number of Mach ports to which the given task has a right.
+// Note that unless the calling task has send rights to the passed task port,
+// this will fail unless the calling task is running as root.
+kern_return_t BASE_EXPORT GetNumberOfMachPorts(mach_port_t task_port,
+                                               int* port_count);
+
+}  // namespace mac
+
 }  // namespace base
 
 #endif // BASE_MACH_IPC_MAC_H_