CSS Tokenizer: Add an on-stack tokenizer scope

Source/core/css/parser/SizesCalcParserTest.cpp

Index: Source/core/css/parser/SizesCalcParserTest.cpp
diff --git a/Source/core/css/parser/SizesCalcParserTest.cpp b/Source/core/css/parser/SizesCalcParserTest.cpp
index d3592323037d23570d94b0cb2ae0b38973a9e3ec..8fcd90c3831bf3428a2614d03ca48db1636ef6c0 100644
--- a/Source/core/css/parser/SizesCalcParserTest.cpp
+++ b/Source/core/css/parser/SizesCalcParserTest.cpp
@@ -117,9 +117,7 @@ TEST(SizesCalcParserTest, Basic)
     RefPtr<MediaValues> mediaValues = MediaValuesCached::create(data);
 
     for (unsigned i = 0; testCases[i].input; ++i) {
-        Vector<CSSParserToken> tokens;
-        CSSTokenizer::tokenize(testCases[i].input, tokens);
-        SizesCalcParser calcParser(CSSParserTokenRange(tokens), mediaValues);
+        SizesCalcParser calcParser(CSSTokenizer::Scope(testCases[i].input).tokenRange(), mediaValues);
         ASSERT_EQ(testCases[i].valid, calcParser.isValid());
         if (calcParser.isValid())
             ASSERT_EQ(testCases[i].output, calcParser.result());