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

base/process/process_metrics_win.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 <windows.h>
 #include <psapi.h>
 #include <stddef.h>
 #include <stdint.h>
@@ skipping 63 matching lines @@
 // Returns the peak working set size, in bytes.
 size_t ProcessMetrics::GetPeakWorkingSetSize() const {
   PROCESS_MEMORY_COUNTERS pmc;
   if (GetProcessMemoryInfo(process_, &pmc, sizeof(pmc))) {
     return pmc.PeakWorkingSetSize;
   }
   return 0;
 }
 
 bool ProcessMetrics::GetMemoryBytes(size_t* private_bytes,
-                                    size_t* shared_bytes) {
+                                    size_t* shared_bytes) const {
   // PROCESS_MEMORY_COUNTERS_EX is not supported until XP SP2.
   // GetProcessMemoryInfo() will simply fail on prior OS. So the requested
   // information is simply not available. Hence, we will return 0 on unsupported
   // OSes. Unlike most Win32 API, we don't need to initialize the "cb" member.
   PROCESS_MEMORY_COUNTERS_EX pmcx;
   if (private_bytes &&
       GetProcessMemoryInfo(process_,
                            reinterpret_cast<PROCESS_MEMORY_COUNTERS*>(&pmcx),
                            sizeof(pmcx))) {
     *private_bytes = pmcx.PrivateUsage;
@@ skipping 265 matching lines @@
 
   meminfo->total = mem_status.ullTotalPhys / 1024;
   meminfo->free = mem_status.ullAvailPhys / 1024;
   meminfo->swap_total = mem_status.ullTotalPageFile / 1024;
   meminfo->swap_free = mem_status.ullAvailPageFile / 1024;
 
   return true;
 }
 
 }  // namespace base