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

ipc/test_util_mac.h

Index: ipc/test_util_mac.h
diff --git a/ipc/test_util_mac.h b/ipc/test_util_mac.h
index 6dd2131ab9df87f572301677a866de3749513799..e976ce0a3c3e5acad8a453212ffc0c17c17a3da7 100644
--- a/ipc/test_util_mac.h
+++ b/ipc/test_util_mac.h
@@ -2,7 +2,8 @@
 // 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_
@@ -42,6 +43,10 @@ void SendMachPort(mach_port_t receiving_port,
 // 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);