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

base/sys_info.cc

 // 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.
 
 #include "base/sys_info.h"
 
+#include "base/base_switches.h"
+#include "base/command_line.h"
+#include "base/lazy_instance.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/sys_info_internal.h"
 #include "base/time/time.h"
 
 namespace base {
 
+#if !defined(OS_ANDROID)
+
+static const int kLowMemoryDeviceThresholdMB = 512;
+
+bool DetectLowEndDevice() {
+  CommandLine* command_line = CommandLine::ForCurrentProcess();
+  int int_value = 0;
+  if (command_line->HasSwitch(switches::kLowEndDeviceMode)) {
+    std::string string_value =
+      command_line->GetSwitchValueASCII(switches::kLowEndDeviceMode);
+    StringToInt(string_value, &int_value);
+  }
+  if (int_value == 1)
+    return true;
+  if (int_value != 2)
+    return false;
+
+  int ram_size_mb = SysInfo::AmountOfPhysicalMemoryMB();
+  return (ram_size_mb > 0 && ram_size_mb < kLowMemoryDeviceThresholdMB);
+}
+
+static LazyInstance<
+  internal::LazySysInfoValue<bool, DetectLowEndDevice> >::Leaky
+  g_lazy_low_end_device = LAZY_INSTANCE_INITIALIZER;
+
+// static
+bool SysInfo::IsLowEndDevice() {
+  return g_lazy_low_end_device.Get().value();
+}
+#endif
+
 // static
 int64 SysInfo::Uptime() {
   // This code relies on an implementation detail of TimeTicks::Now() - that
   // its return value happens to coincide with the system uptime value in
   // microseconds, on Win/Mac/iOS/Linux/ChromeOS and Android.
   int64 uptime_in_microseconds = TimeTicks::Now().ToInternalValue();
   return uptime_in_microseconds / 1000;
 }
 
 }  // namespace base