GN: aix port along with linux_s390x, linux_ppc64 and linux_ppc64le support.

base/process/process_handle.cc

 // 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.
 
 #include <stdint.h>
 
 #include "base/logging.h"
 #include "base/process/process_handle.h"
 #include "build/build_config.h"
 
@@ skipping 21 matching lines @@
     return MangleProcessId(GetCurrentProcId());
   }
 
   // Make sure we are the same process that set |g_procid|. This check may have
   // false negatives (if a process ID was reused) but should have no false
   // positives.
   DCHECK_EQ(GetCurrentProcId(), g_procid);
   return g_unique_id;
 }
 
-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(OS_AIX)
 
 void InitUniqueIdForProcessInPidNamespace(ProcessId pid_outside_of_namespace) {
   g_unique_id = MangleProcessId(pid_outside_of_namespace);
   g_procid = GetCurrentProcId();
   g_have_unique_id = true;
 }
 
 #endif
 
 }  // namespace base