Removed O(n!) traversal of selectors for selectorList.

Source/core/css/RuleFeature.cpp

Index: Source/core/css/RuleFeature.cpp
diff --git a/Source/core/css/RuleFeature.cpp b/Source/core/css/RuleFeature.cpp
index 1395acf0e6f59aca9dfcef749802b97bc3626a39..6d627baacf30c338159d4e2e5fc689f0ba902d00 100644
--- a/Source/core/css/RuleFeature.cpp
+++ b/Source/core/css/RuleFeature.cpp
@@ -211,10 +211,8 @@ void RuleFeatureSet::collectFeaturesFromSelectorList(const CSSSelectorList* sele
     if (!selectorList)
         return;
 
-    for (const CSSSelector* selector = selectorList->first(); selector; selector = CSSSelectorList::next(*selector)) {
-        for (const CSSSelector* subSelector = selector; subSelector; subSelector = subSelector->tagHistory())
-            collectFeaturesFromSelector(*subSelector, metadata, collectionMode);
-    }
+    for (const CSSSelector* selector = selectorList->first(); selector; selector = CSSSelectorList::next(*selector))
+        collectFeaturesFromSelector(*selector, metadata, collectionMode);
 }
 
 void RuleFeatureSet::FeatureMetadata::add(const FeatureMetadata& other)