Replace FINAL and OVERRIDE with their C++11 counterparts in Source/core/[css|rendering|clipboard]

Source/core/css/Pair.h

Index: Source/core/css/Pair.h
diff --git a/Source/core/css/Pair.h b/Source/core/css/Pair.h
index d686a57e2bb8128f2d881625f16ceb63d7c70a34..dca72783ff3d3c80ae3156b791a0520f4f708c11 100644
--- a/Source/core/css/Pair.h
+++ b/Source/core/css/Pair.h
@@ -32,7 +32,7 @@ namespace blink {
 // and border-spacing (all of which are space-separated sets of two values).  At the moment we are only using it for
 // border-radius and background-size, but (FIXME) border-spacing and background-position could be converted over to use
 // it (eliminating some extra -webkit- internal properties).
-class Pair FINAL : public RefCountedWillBeGarbageCollected<Pair> {
+class Pair final : public RefCountedWillBeGarbageCollected<Pair> {
 public:
     enum IdenticalValuesPolicy { DropIdenticalValues, KeepIdenticalValues };