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

base/process/process_handle_linux.cc

 // Copyright (c) 2013 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 "base/process/process_handle.h"
 
 #include "base/files/file_util.h"
 #include "base/process/internal_linux.h"
+#if defined(OS_AIX)
+#include "base/process/internal_aix.h"
+#endif
 
 namespace base {
 
 ProcessId GetParentProcessId(ProcessHandle process) {
   ProcessId pid =
+#if defined(OS_AIX)
+      internalAIX::ReadProcStatsAndGetFieldAsInt64(process,
+                                                   internalAIX::VM_PPID);
+#else
       internal::ReadProcStatsAndGetFieldAsInt64(process, internal::VM_PPID);
+#endif
   if (pid)
     return pid;
   return -1;
 }
 
 FilePath GetProcessExecutablePath(ProcessHandle process) {
   FilePath stat_file = internal::GetProcPidDir(process).Append("exe");
   FilePath exe_name;
   if (!ReadSymbolicLink(stat_file, &exe_name)) {
     // No such process.  Happens frequently in e.g. TerminateAllChromeProcesses
     return FilePath();
   }
   return exe_name;
 }
 
 }  // namespace base