mac: Fix calulation for number of resident pages in a process.

base/process/process_metrics_openbsd.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_metrics.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <sys/param.h>
 #include <sys/sysctl.h>
@@ skipping 46 matching lines @@
     return -1;
 
   return info.p_vm_rssize * getpagesize();
 }
 
 size_t ProcessMetrics::GetPeakWorkingSetSize() const {
   return 0;
 }
 
 bool ProcessMetrics::GetMemoryBytes(size_t* private_bytes,
-                                    size_t* shared_bytes) {
+                                    size_t* shared_bytes) const {
   WorkingSetKBytes ws_usage;
 
   if (!GetWorkingSetKBytes(&ws_usage))
     return false;
 
   if (private_bytes)
     *private_bytes = ws_usage.priv << 10;
 
   if (shared_bytes)
     *shared_bytes = ws_usage.shared * 1024;
@@ skipping 79 matching lines @@
   mem_total = vmtotal.t_vm;
   mem_free = vmtotal.t_free;
   mem_inactive = vmtotal.t_vm - vmtotal.t_avm;
 
   pagesize = getpagesize();
 
   return mem_total - (mem_free*pagesize) - (mem_inactive*pagesize);
 }
 
 }  // namespace base