Update from https://crrev.com/309415

base/process/process_metrics_ios.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 <mach/task.h>
 
 namespace base {
 
@@ skipping 47 matching lines @@
   if (max_fds > INT_MAX)
     max_fds = INT_MAX;
 
   return static_cast<size_t>(max_fds);
 }
 
 void SetFdLimit(unsigned int max_descriptors) {
   // Unimplemented.
 }
 
+size_t GetPageSize() {
+  return getpagesize();
+}
+
 }  // namespace base