Standardize usage of virtual/override/final specifiers in ui/.

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11_unittest.cc

Index: ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11_unittest.cc
diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11_unittest.cc b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11_unittest.cc
index a40cca757ddae0c81cd669f8d023ff25791702de..0eae9dc09b4a2e16fd8ac3cd4e50802d2fa52dc7 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11_unittest.cc
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11_unittest.cc
@@ -796,7 +796,7 @@ class TestDragDropDelegate : public aura::client::DragDropDelegate {
     ++num_exits_;
   }
 
-  virtual int OnPerformDrop(const ui::DropTargetEvent& event) override {
+  int OnPerformDrop(const ui::DropTargetEvent& event) override {
     ++num_drops_;
     last_event_mouse_position_ = event.location();
     last_event_flags_ = event.flags();