Improve and unify Mac OS X run-time version checks

chrome/browser/process_info_snapshot_mac.cc

 // Copyright (c) 2011 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 "chrome/browser/process_info_snapshot.h"
 
 #include <sys/sysctl.h>
 
 #include <sstream>
 
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/mac/mac_util.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
-#include "base/sys_info.h"
 #include "base/threading/thread.h"
 
 // Default constructor.
 ProcessInfoSnapshot::ProcessInfoSnapshot() { }
 
 // Destructor: just call |Reset()| to release everything.
 ProcessInfoSnapshot::~ProcessInfoSnapshot() {
   Reset();
 }
 
@@ skipping 347 matching lines @@
        it != pid_list.end(); ++it) {
     std::string exectuable_name;
     if (GetExecutableNameForProcessID(*it, &exectuable_name)) {
       ProcInfoEntry proc_info = proc_info_entries_[*it];
       proc_info.command = exectuable_name;
     }
   }
 
   // Get memory information using top.
   bool memory_info_success = false;
-  int32 major, minor, bugfix;
-  base::SysInfo::OperatingSystemVersionNumbers(&major, &minor, &bugfix);
-  if (major == 10 && minor == 5)
+  if (base::mac::IsOSLeopardOrEarlier())
     memory_info_success = GetProcessMemoryInfoUsingTop_10_5(proc_info_entries_);
-  else if ((major == 10 && minor >= 6) || major > 10)
+  else
     memory_info_success = GetProcessMemoryInfoUsingTop(proc_info_entries_);
 
   // If top didn't work then fall back to ps.
   if (!memory_info_success) {
     memory_info_success = GetProcessMemoryInfoUsingPS(pid_list,
                                                       proc_info_entries_);
   }
 
   return memory_info_success;
 }
@@ skipping 53 matching lines @@
     ws_usage->shareable = 0;
     ws_usage->shared = 0;
     return false;
   }
 
   ws_usage->priv = proc_info.rprvt / 1024;
   ws_usage->shareable = proc_info.rss / 1024;
   ws_usage->shared = proc_info.rshrd / 1024;
   return true;
 }