Change Counter to be a CSSValue

Source/core/css/Counter.cpp

Index: Source/core/css/Counter.cpp
diff --git a/Source/core/css/Counter.cpp b/Source/core/css/Counter.cpp
deleted file mode 100644
index e519585aff24c747a6873b8c4ae48281e10497d1..0000000000000000000000000000000000000000
--- a/Source/core/css/Counter.cpp
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "config.h"
-#include "core/css/Counter.h"
-
-namespace blink {
-
-DEFINE_TRACE(Counter)
-{
-    visitor->trace(m_identifier);
-    visitor->trace(m_listStyle);
-    visitor->trace(m_separator);
-}
-
-}