Move Singleton and related structs to namespace base

content/browser/device_sensors/sensor_manager_android.cc

Index: content/browser/device_sensors/sensor_manager_android.cc
diff --git a/content/browser/device_sensors/sensor_manager_android.cc b/content/browser/device_sensors/sensor_manager_android.cc
index f63e45a91ffa16af1a793d70664bce5c71dd3a73..d29058766f81c4ff000b9f83c1b2208ceb25a899 100644
--- a/content/browser/device_sensors/sensor_manager_android.cc
+++ b/content/browser/device_sensors/sensor_manager_android.cc
@@ -58,8 +58,9 @@ bool SensorManagerAndroid::Register(JNIEnv* env) {
 }
 
 SensorManagerAndroid* SensorManagerAndroid::GetInstance() {
-  return Singleton<SensorManagerAndroid,
-                   LeakySingletonTraits<SensorManagerAndroid> >::get();
+  return base::Singleton<
+      SensorManagerAndroid,
+      base::LeakySingletonTraits<SensorManagerAndroid>>::get();
 }
 
 void SensorManagerAndroid::GotOrientation(