Update from https://crrev.com/309415

base/process/process_metrics.h

 // 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.
 
 // This file contains routines for gathering resource statistics for processes
 // running on the system.
 
 #ifndef BASE_PROCESS_PROCESS_METRICS_H_
 #define BASE_PROCESS_PROCESS_METRICS_H_
 
@@ skipping 213 matching lines @@
 #endif  // defined(OS_POSIX)
 #endif  // !defined(OS_IOS)
 
   DISALLOW_COPY_AND_ASSIGN(ProcessMetrics);
 };
 
 // Returns the memory committed by the system in KBytes.
 // Returns 0 if it can't compute the commit charge.
 BASE_EXPORT size_t GetSystemCommitCharge();
 
+// Returns the number of bytes in a memory page.
+BASE_EXPORT size_t GetPageSize();
+
 #if defined(OS_POSIX)
 // Returns the maximum number of file descriptors that can be open by a process
 // at once. If the number is unavailable, a conservative best guess is returned.
 BASE_EXPORT size_t GetMaxFds();
 
 // Sets the file descriptor soft limit to |max_descriptors| or the OS hard
 // limit, whichever is lower.
 BASE_EXPORT void SetFdLimit(unsigned int max_descriptors);
 #endif  // defined(OS_POSIX)
 
@@ skipping 139 matching lines @@
   SystemDiskInfo disk_info_;
 #endif
 #if defined(OS_CHROMEOS)
   SwapInfo swap_info_;
 #endif
 };
 
 }  // namespace base
 
 #endif  // BASE_PROCESS_PROCESS_METRICS_H_