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

base/sys_info.cc

Index: base/sys_info.cc
diff --git a/base/sys_info.cc b/base/sys_info.cc
index d43e9320bc4ec2a4898fd372cd363be3d46d8e02..0b3b317fc8bf2a92a72bcf2991af8da3470ac2b0 100644
--- a/base/sys_info.cc
+++ b/base/sys_info.cc
@@ -4,10 +4,46 @@
 
 #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