Remove CloseProcessHandle.

base/process/process_handle_posix.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 <unistd.h>
 
 namespace base {
 
 ProcessId GetCurrentProcId() {
   return getpid();
 }
 
 ProcessHandle GetCurrentProcessHandle() {
   return GetCurrentProcId();
 }
 
-void CloseProcessHandle(ProcessHandle process) {
-  // See OpenProcessHandle, nothing to do.
-  return;
-}
-
 ProcessId GetProcId(ProcessHandle process) {
   return process;
 }
 
 }  // namespace base