Expose a low-end device mode override flags for non-android OSs as well

base/sys_utils.cc

+// Copyright 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/sys_utils.h"
+
+#include "base/base_switches.h"
+#include "base/command_line.h"
+#include "base/lazy_instance.h"
+#include "base/sys_info.h"
+#include "base/sys_info_internal.h"
+
+#if !defined(OS_ANDROID)
+namespace {
+static const int kLowMemoryDeviceThresholdMB = 512;
+
+bool detectLowEndDevice() {

[piman, 2014/04/24 19:50:08]

nit: style

[c.shu, 2014/06/10 17:36:26]

Done.

+  CommandLine* command_line = CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kEnableLowEndDeviceMode )) {
+      return true;
+  }
+  if (command_line->HasSwitch(switches::kDisableLowEndDeviceMode)) {
+      return false;
+  }
+
+  if (command_line->HasSwitch(switches::kDetectLowEndDevice)) {
+    int ram_size_mb = base::SysInfo::AmountOfPhysicalMemoryMB();
+    return (ram_size_mb > 0 && ram_size_mb < kLowMemoryDeviceThresholdMB);
+  }
+  return false;
+}
+
+static base::LazyInstance<
+    base::internal::LazySysInfoValue<bool, detectLowEndDevice> >::Leaky
+    g_lazy_low_end_device = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+namespace base {
+// static
+bool SysUtils::IsLowEndDevice() {
+  return g_lazy_low_end_device.Get().value();

[piman, 2014/04/24 19:50:08]

This won't work in subprocesses unless:
1- command-line flags are passed through to those subprocesses
2- this is evaluated/cached before the sandbox is turned on
(AmountOfPhysicalMemoryMB is done via sysconf, by openning /proc/meminfo, which
is not allowed in the sandbox).

+}
+}  // namespace base
+#endif
+
+namespace base {
+// static
+size_t SysUtils::AmountOfPhysicalMemoryKB() {
+  return SysInfo::AmountOfPhysicalMemory() / 1024;
+}
+
+SysUtils::SysUtils() { }
+}  // namespace base