Reland "Enable SysInfo::AmountOfPhysicalMemory to be called from within the Linux Sandbox"

base/sys_info.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_SYS_INFO_H_
 #define BASE_SYS_INFO_H_
 
 #include <map>
 #include <string>
 
@@ skipping 57 matching lines @@
   // http://crbug.com/148884
   // Returns the CPU model name of the system. If it can not be figured out,
   // an empty string is returned.
   static std::string CPUModelName();
 
   // Return the smallest amount of memory (in bytes) which the VM system will
   // allocate.
   static size_t VMAllocationGranularity();
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
-  // Returns the maximum SysV shared memory segment size.
+  // Returns the maximum SysV shared memory segment size, or zero if there is no
+  // limit.
   static size_t MaxSharedMemorySize();
 #endif  // defined(OS_POSIX) && !defined(OS_MACOSX)
 
 #if defined(OS_CHROMEOS)
   typedef std::map<std::string, std::string> LsbReleaseMap;
 
   // Returns the contents of /etc/lsb-release as a map.
   static const LsbReleaseMap& GetLsbReleaseMap();
 
   // If |key| is present in the LsbReleaseMap, sets |value| and returns true.
@@ skipping 26 matching lines @@
   static std::string GetDeviceName();
 
   static int DalvikHeapSizeMB();
   static int DalvikHeapGrowthLimitMB();
 #endif  // defined(OS_ANDROID)
 };
 
 }  // namespace base
 
 #endif  // BASE_SYS_INFO_H_