Stop emitting physical footprint on macOS 10.11.

base/process/process_metrics_mac.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/mach.h>
 #include <mach/mach_vm.h>
 #include <mach/shared_region.h>
 #include <stddef.h>
@@ skipping 270 matching lines @@
   usage->image = 0;
 
   ws_usage->priv = task_info_data.resident_size / 1024;
   ws_usage->shareable = 0;
   ws_usage->shared = 0;
 
   return true;
 }
 
 size_t ProcessMetrics::GetPhysicalFootprint() const {
-  if (mac::IsAtMostOS10_10())
+  if (mac::IsAtMostOS10_11())
     return 0;
 
   ChromeTaskVMInfo task_vm_info;
   mach_msg_type_number_t count = ChromeTaskVMInfoCount;
   kern_return_t result =
       task_info(TaskForPid(process_), TASK_VM_INFO,
                 reinterpret_cast<task_info_t>(&task_vm_info), &count);

[Mark Mentovai, 2017/04/24 23:57:21]

Note that you can also get rid of the OS version check and verify that “count”
on the way out >= (or ==) ChromeTaskVMInfoCount.

[erikchen, 2017/04/25 00:19:05]

I'd like to avoid a syscall when I know the results are not going to be
meaningful.

   if (result != KERN_SUCCESS)
     return 0;
   return task_vm_info.phys_footprint;
 }
 
 #define TIME_VALUE_TO_TIMEVAL(a, r) do {  \
   (r)->tv_sec = (a)->seconds;             \
   (r)->tv_usec = (a)->microseconds;       \
 } while (0)
 
@@ skipping 186 matching lines @@
       task, address, size, VM_REGION_BASIC_INFO_64,
       reinterpret_cast<vm_region_info_t>(info), &info_count, &object_name);
   // The kernel always returns a null object for VM_REGION_BASIC_INFO_64, but
   // balance it with a deallocate in case this ever changes. See 10.9.2
   // xnu-2422.90.20/osfmk/vm/vm_map.c vm_map_region.
   mach_port_deallocate(task, object_name);
   return ParseOutputFromMachVMRegion(kr);
 }
 
 }  // namespace base