replace OVERRIDE and FINAL with override and final in ash/

ash/desktop_background/desktop_background_controller_unittest.cc

Index: ash/desktop_background/desktop_background_controller_unittest.cc
diff --git a/ash/desktop_background/desktop_background_controller_unittest.cc b/ash/desktop_background/desktop_background_controller_unittest.cc
index 01a71594ee0e7b878bc3398fca5897a12adbaa82..e504f030ed40c669bbe8373e3b70fd3b48cd2c99 100644
--- a/ash/desktop_background/desktop_background_controller_unittest.cc
+++ b/ash/desktop_background/desktop_background_controller_unittest.cc
@@ -73,7 +73,7 @@ class DesktopBackgroundControllerTest : public test::AshTestBase {
   }
   virtual ~DesktopBackgroundControllerTest() {}
 
-  virtual void SetUp() OVERRIDE {
+  virtual void SetUp() override {
     test::AshTestBase::SetUp();
     // Ash shell initialization creates wallpaper. Reset it so we can manually
     // control wallpaper creation and animation in our tests.