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

base/process/process_handle_linux.cc

Index: base/process/process_handle_linux.cc
diff --git a/base/process/process_handle_linux.cc b/base/process/process_handle_linux.cc
index 950b888cfaa11f8331cf72c4c4c4f3fd6f160898..3a0460725e0d44f5639586ad4c0c5ad30b12c99d 100644
--- a/base/process/process_handle_linux.cc
+++ b/base/process/process_handle_linux.cc
@@ -6,12 +6,20 @@
 
 #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;