CSS Tokenizer: Add an on-stack tokenizer scope

Source/core/css/parser/SizesAttributeParser.cpp

 // 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/parser/SizesAttributeParser.h"
 
 #include "core/MediaTypeNames.h"
 #include "core/css/MediaQueryEvaluator.h"
 #include "core/css/parser/CSSTokenizer.h"
 #include "core/css/parser/SizesCalcParser.h"
 
 namespace blink {
 
 SizesAttributeParser::SizesAttributeParser(PassRefPtr<MediaValues> mediaValues, const String& attribute)
     : m_mediaValues(mediaValues)
     , m_length(0)
     , m_lengthWasSet(false)
 {
-    CSSTokenizer::tokenize(attribute, m_tokens);
-    m_isValid = parse(m_tokens);
+    m_isValid = parse(CSSTokenizer::Scope(attribute).tokenRange());
 }
 
 float SizesAttributeParser::length()
 {
     if (m_isValid)
         return effectiveSize();
     return effectiveSizeDefaultValue();
 }
 
 bool SizesAttributeParser::calculateLengthInPixels(CSSParserTokenRange range, float& result)
@@ skipping 22 matching lines @@
     return false;
 }
 
 bool SizesAttributeParser::mediaConditionMatches(PassRefPtrWillBeRawPtr<MediaQuerySet> mediaCondition)
 {
     // A Media Condition cannot have a media type other then screen.
     MediaQueryEvaluator mediaQueryEvaluator(*m_mediaValues);
     return mediaQueryEvaluator.eval(mediaCondition.get());
 }
 
-bool SizesAttributeParser::parse(Vector<CSSParserToken>& tokens)
+bool SizesAttributeParser::parse(CSSParserTokenRange range)
 {
-    CSSParserTokenRange range(tokens);
     // Split on a comma token and parse the result tokens as (media-condition, length) pairs
     while (!range.atEnd()) {
         const CSSParserToken* mediaConditionStart = &range.peek();
         // The length is the last component value before the comma which isn't whitespace or a comment
         const CSSParserToken* lengthTokenStart = &range.peek();
         const CSSParserToken* lengthTokenEnd = &range.peek();
         while (!range.atEnd() && range.peek().type() != CommaToken) {
             lengthTokenStart = &range.peek();
             range.consumeComponentValue();
             lengthTokenEnd = &range.peek();
@@ skipping 21 matching lines @@
     return effectiveSizeDefaultValue();
 }
 
 unsigned SizesAttributeParser::effectiveSizeDefaultValue()
 {
     // Returning the equivalent of "100vw"
     return m_mediaValues->viewportWidth();
 }
 
 } // namespace