CSS Tokenizer: Add an on-stack tokenizer scope

Source/core/css/parser/CSSSelectorParserTest.cpp

 // Copyright 2015 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/CSSSelectorParser.h"
 
 #include "core/css/parser/CSSTokenizer.h"
 #include <gtest/gtest.h>
 
@@ skipping 55 matching lines @@
         {"+n + 61", 1, 61},
         {"+N - 63", 1, -63},
         {"+n/**/- 48", 1, -48},
         {"-n + 81", -1, 81},
         {"-N - 88", -1, -88},
     };
 
     for (unsigned i = 0; i < WTF_ARRAY_LENGTH(testCases); ++i) {
         SCOPED_TRACE(testCases[i].input);
 
-        Vector<CSSParserToken> tokens;
-        CSSTokenizer::tokenize(testCases[i].input, tokens);
-        CSSParserTokenRange range(tokens);
-
         std::pair<int, int> ab;
+        CSSTokenizer::Scope scope(testCases[i].input);
+        CSSParserTokenRange range = scope.tokenRange();
         bool passed = CSSSelectorParser::consumeANPlusB(range, ab);
         EXPECT_TRUE(passed);
         EXPECT_EQ(ab.first, testCases[i].a);
         EXPECT_EQ(ab.second, testCases[i].b);
     }
 }
 
 TEST(CSSSelectorParserTest, InvalidANPlusB)
 {
     // Some of these have token range prefixes which are valid <an+b> and could
     // in theory be valid in consumeANPlusB, but this behaviour isn't needed
     // anywhere and not implemented.
     const char* testCases[] = {
         " odd",
         "+ n",
         "3m+4",
         "12n--34",
         "12n- -34",
         "12n- +34",
         "23n-+43",
         "10n 5",
         "10n + +5",
         "10n + -5",
     };
 
     for (unsigned i = 0; i < WTF_ARRAY_LENGTH(testCases); ++i) {
         SCOPED_TRACE(testCases[i]);
 
-        Vector<CSSParserToken> tokens;
-        CSSTokenizer::tokenize(testCases[i], tokens);
-        CSSParserTokenRange range(tokens);
-
         std::pair<int, int> ab;
+        CSSTokenizer::Scope scope(testCases[i]);
+        CSSParserTokenRange range = scope.tokenRange();
         bool passed = CSSSelectorParser::consumeANPlusB(range, ab);
         EXPECT_FALSE(passed);
     }
 }
 
 } // namespace