CSS Tokenizer: Add an on-stack tokenizer scope

Source/core/css/parser/CSSTokenizer.h

 // 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.
 
 #ifndef CSSTokenizer_h
 #define CSSTokenizer_h
 
 #include "core/css/parser/CSSParserToken.h"
 #include "core/html/parser/InputStreamPreprocessor.h"
 #include "wtf/text/WTFString.h"
 
 #include <climits>
 
 namespace blink {
 
 class CSSTokenizerInputStream;
+class CSSParserTokenRange;
 
 class CSSTokenizer {
     WTF_MAKE_NONCOPYABLE(CSSTokenizer);
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    static void tokenize(String, Vector<CSSParserToken>&);
+    class Scope {
+    public:
+        Scope(const String&);
+        CSSParserTokenRange tokenRange();
+
+    private:
+        Vector<CSSParserToken> m_tokens;
+    };
+
 private:
     CSSTokenizer(CSSTokenizerInputStream&);
 
     CSSParserToken nextToken();
 
     UChar consume();
     void consume(unsigned);
     void reconsume(UChar);
 
     CSSParserToken consumeNumericToken();
@@ skipping 55 matching lines @@
     CSSParserToken endOfFile(UChar);
 
     CSSTokenizerInputStream& m_input;
 };
 
 
 
 } // namespace blink
 
 #endif // CSSTokenizer_h