Move OpenProcessHandle to Process::Open.

base/process/process_handle_posix.cc

Index: base/process/process_handle_posix.cc
diff --git a/base/process/process_handle_posix.cc b/base/process/process_handle_posix.cc
index 3d92300a7bcadf809559aefdcd46bccb12d0c4fb..a661ecd899b493ee31771c55d854989a20f02e62 100644
--- a/base/process/process_handle_posix.cc
+++ b/base/process/process_handle_posix.cc
@@ -16,13 +16,6 @@ ProcessHandle GetCurrentProcessHandle() {
   return GetCurrentProcId();
 }
 
-bool OpenProcessHandle(ProcessId pid, ProcessHandle* handle) {
-  // On Posix platforms, process handles are the same as PIDs, so we
-  // don't need to do anything.
-  *handle = pid;
-  return true;
-}
-
 void CloseProcessHandle(ProcessHandle process) {
   // See OpenProcessHandle, nothing to do.
   return;