Replace FINAL and OVERRIDE with their C++11 counterparts in Source/core/editing

Source/core/editing/UndoStack.h

Index: Source/core/editing/UndoStack.h
diff --git a/Source/core/editing/UndoStack.h b/Source/core/editing/UndoStack.h
index 2839e536035b37c86fe10ad6a8fe86f600c65c69..d9e0fa143c2616e2f17c404fce3d75d7b86a4b0c 100644
--- a/Source/core/editing/UndoStack.h
+++ b/Source/core/editing/UndoStack.h
@@ -40,7 +40,7 @@ namespace blink {
 class LocalFrame;
 class UndoStep;
 
-class UndoStack FINAL : public NoBaseWillBeGarbageCollected<UndoStack> {
+class UndoStack final : public NoBaseWillBeGarbageCollected<UndoStack> {
     DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(UndoStack)
 public:
     static PassOwnPtrWillBeRawPtr<UndoStack> create();