Move Singleton and related structs to namespace base

ui/base/ime/input_method_auralinux_unittest.cc

Index: ui/base/ime/input_method_auralinux_unittest.cc
diff --git a/ui/base/ime/input_method_auralinux_unittest.cc b/ui/base/ime/input_method_auralinux_unittest.cc
index 2cd15008b9df173d75046f30a3e902a3e5e4c9b7..7716e9ed049d7a934c05dffdb971c17d14e9766f 100644
--- a/ui/base/ime/input_method_auralinux_unittest.cc
+++ b/ui/base/ime/input_method_auralinux_unittest.cc
@@ -25,7 +25,9 @@ const base::char16 kActionCompositionEnd = L'E';
 
 class TestResult {
  public:
-  static TestResult* GetInstance() { return Singleton<TestResult>::get(); }
+  static TestResult* GetInstance() {
+    return base::Singleton<TestResult>::get();
+  }
 
   void RecordAction(const base::string16& action) {
     recorded_actions_.push_back(action);