RFC: Make BisonCSSParser purely stack allocated.

Source/core/css/parser/BisonCSSParser.h

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 - 2010  Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 60 matching lines @@
 class UseCounter;
 
 // FIXME: This class is shared with CSSTokenizer so should we rename it to CSSSourceLocation?
 struct CSSParserLocation {
     unsigned offset;
     unsigned lineNumber;
     CSSParserString token;
 };
 
 class BisonCSSParser {
+    STACK_ALLOCATED();
     friend inline int cssyylex(void*, BisonCSSParser*);
-
 public:
-    BisonCSSParser(const CSSParserContext&);
+    explicit BisonCSSParser(const CSSParserContext&);
     ~BisonCSSParser();
 
     void rollbackLastProperties(int num);
     void setCurrentProperty(CSSPropertyID);
 
     void parseSheet(StyleSheetContents*, const String&, const TextPosition& startPosition = TextPosition::minimumPosition(), CSSParserObserver* = 0, bool = false);
     PassRefPtrWillBeRawPtr<StyleRuleBase> parseRule(StyleSheetContents*, const String&);
     PassRefPtrWillBeRawPtr<StyleKeyframe> parseKeyframeRule(StyleSheetContents*, const String&);
     bool parseSupportsCondition(const String&);
     static bool parseValue(MutableStylePropertySet*, CSSPropertyID, const String&, bool important, CSSParserMode, StyleSheetContents*);
@@ skipping 224 matching lines @@
 inline int cssyylex(void* yylval, BisonCSSParser* parser)
 {
     return parser->m_tokenizer.lex(yylval);
 }
 
 bool isValidNthToken(const CSSParserString&);
 
 } // namespace WebCore
 
 #endif // BisonCSSParser_h