[test] lazily parse css style rules

third_party/WebKit/Source/core/css/parser/CSSParserImpl.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 CSSParserImpl_h
 #define CSSParserImpl_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/css/CSSProperty.h"
 #include "core/css/CSSPropertySourceData.h"
@@ skipping 54 matching lines @@
     static void parseStyleSheet(const String&, const CSSParserContext&, StyleSheetContents*);
     static CSSSelectorList parsePageSelector(CSSParserTokenRange, StyleSheetContents*);
 
     static ImmutableStylePropertySet* parseCustomPropertySet(CSSParserTokenRange);
 
     static std::unique_ptr<Vector<double>> parseKeyframeKeyList(const String&);
 
     bool supportsDeclaration(CSSParserTokenRange&);
 
     static void parseDeclarationListForInspector(const String&, const CSSParserContext&, CSSParserObserver&);
+    static ImmutableStylePropertySet* parseDeclarationListForLazyStyle(CSSParserTokenRange, const CSSParserContext&);
     static void parseStyleSheetForInspector(const String&, const CSSParserContext&, StyleSheetContents*, CSSParserObserver&);
 
+    void enableLazyParsing() { m_shouldUseLazyParsing = true; }
+
 private:
     enum RuleListType {
         TopLevelRuleList,
         RegularRuleList,
         KeyframesRuleList
     };
 
     // Returns whether the first encountered rule was valid
     template<typename T>
     bool consumeRuleList(CSSParserTokenRange, RuleListType, T callback);
@@ skipping 26 matching lines @@
 
     // FIXME: Can we build StylePropertySets directly?
     // FIXME: Investigate using a smaller inline buffer
     HeapVector<CSSProperty, 256> m_parsedProperties;
     const CSSParserContext& m_context;
 
     Member<StyleSheetContents> m_styleSheet;
 
     // For the inspector
     CSSParserObserverWrapper* m_observerWrapper;
+
+    // Right now, just enable lazy parsing when we parse a whole sheet.
+    bool m_shouldUseLazyParsing = false;
 };
 
 } // namespace blink
 
 #endif // CSSParserImpl_h