[test] lazily parse css style rules

third_party/WebKit/Source/core/css/StyleRule.h

Index: third_party/WebKit/Source/core/css/StyleRule.h
diff --git a/third_party/WebKit/Source/core/css/StyleRule.h b/third_party/WebKit/Source/core/css/StyleRule.h
index f7098ecadac418056cfe9af359b134ddbb27045a..b2e432f149a03e0ba19188ff0b85e035486990ab 100644
--- a/third_party/WebKit/Source/core/css/StyleRule.h
+++ b/third_party/WebKit/Source/core/css/StyleRule.h
@@ -26,6 +26,7 @@
 #include "core/css/CSSSelectorList.h"
 #include "core/css/MediaList.h"
 #include "core/css/StylePropertySet.h"
+#include "core/css/parser/CSSParserTokenRange.h"
 #include "platform/heap/Handle.h"
 #include "wtf/RefPtr.h"
 
@@ -97,11 +98,15 @@ public:
     {
         return new StyleRule(std::move(selectorList), properties);
     }
+    static StyleRule* createLazy(CSSSelectorList selectorList, CSSParserTokenRange tokens, const CSSParserContext* context)
+    {
+        return new StyleRule(std::move(selectorList), tokens, context);
+    }
 
     ~StyleRule();
 
     const CSSSelectorList& selectorList() const { return m_selectorList; }
-    const StylePropertySet& properties() const { return *m_properties; }
+    const StylePropertySet& properties() const;
     MutableStylePropertySet& mutableProperties();
 
     void wrapperAdoptSelectorList(CSSSelectorList selectors) { m_selectorList = std::move(selectors); }
@@ -114,10 +119,14 @@ public:
 
 private:
     StyleRule(CSSSelectorList, StylePropertySet*);
+    StyleRule(CSSSelectorList, CSSParserTokenRange block, const CSSParserContext*);
     StyleRule(const StyleRule&);
 
-    Member<StylePropertySet> m_properties; // Cannot be null.
     CSSSelectorList m_selectorList;
+
+    mutable Member<StylePropertySet> m_properties;
+    mutable Vector<CSSParserToken> m_lazyTokens;
+    const CSSParserContext* m_context;
 };
 
 class StyleRuleFontFace : public StyleRuleBase {