Use invalidation sets for some pseudo elements.

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 34 matching lines @@
 #include "wtf/BitVector.h"
 
 namespace WebCore {
 
 static bool isSkippableComponentForInvalidation(const CSSSelector& selector)
 {
     if (selector.m_match == CSSSelector::Tag
         || selector.m_match == CSSSelector::Id
         || selector.isAttributeSelector())
         return true;
+    if (selector.m_match == CSSSelector::PseudoElement) {
+        switch (selector.m_pseudoType) {
+        case CSSSelector::PseudoBefore:
+        case CSSSelector::PseudoAfter:
+        case CSSSelector::PseudoBackdrop:
+            return true;
+        default:
+            return false;
+        }
+    }
     if (selector.m_match != CSSSelector::PseudoClass)
         return false;
     switch (selector.pseudoType()) {
     case CSSSelector::PseudoEmpty:
     case CSSSelector::PseudoFirstChild:
     case CSSSelector::PseudoFirstOfType:
     case CSSSelector::PseudoLastChild:
     case CSSSelector::PseudoLastOfType:
     case CSSSelector::PseudoOnlyChild:
     case CSSSelector::PseudoOnlyOfType:
@@ skipping 378 matching lines @@
     }
 
     invalidationClasses.remove(oldSize, invalidationClasses.size() - oldSize);
     element->clearChildNeedsStyleInvalidation();
     element->clearNeedsStyleInvalidation();
 
     return thisElementNeedsStyleRecalc;
 }
 
 } // namespace WebCore