Use invalidation set for :empty pseudo changes.

Source/core/css/RuleFeature.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 194 matching lines @@
 
 DescendantInvalidationSet* RuleFeatureSet::invalidationSetForSelector(const CSSSelector& selector)
 {
     if (selector.match() == CSSSelector::Class)
         return &ensureClassInvalidationSet(selector.value());
     if (selector.isAttributeSelector())
         return &ensureAttributeInvalidationSet(selector.attribute().localName());
     if (selector.match() == CSSSelector::Id)
         return &ensureIdInvalidationSet(selector.value());
     if (selector.match() == CSSSelector::PseudoClass) {
-        CSSSelector::PseudoType pseudo = selector.pseudoType();
-        if (pseudo == CSSSelector::PseudoHover || pseudo == CSSSelector::PseudoActive || pseudo == CSSSelector::PseudoFocus)
-            return &ensurePseudoInvalidationSet(pseudo);
+        switch (selector.pseudoType()) {
+        case CSSSelector::PseudoEmpty:
+        case CSSSelector::PseudoHover:
+        case CSSSelector::PseudoActive:
+        case CSSSelector::PseudoFocus:
+            return &ensurePseudoInvalidationSet(selector.pseudoType());
+        default:
+            break;
+        }
     }
     return 0;
 }
 
 // Given a selector, update the descendant invalidation sets for the features found
 // in the selector. The first step is to extract the features from the rightmost
 // compound selector (extractInvalidationSetFeatures). Secondly, those features will be
 // added to the invalidation sets for the features found in the other compound selectors
 // (addFeaturesToInvalidationSets).
 
@@ skipping 332 matching lines @@
     visitor->trace(uncommonAttributeRules);
     visitor->trace(m_classInvalidationSets);
     visitor->trace(m_attributeInvalidationSets);
     visitor->trace(m_idInvalidationSets);
     visitor->trace(m_pseudoInvalidationSets);
     visitor->trace(m_styleInvalidator);
 #endif
 }
 
 } // namespace blink