Don't schedule invalidations when attributes changed if not needed or incorrect.

Source/core/dom/Element.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 798 matching lines @@
     return isElementNode() && toElement(this)->hasID();
 }
 
 inline bool Node::hasClass() const
 {
     return isElementNode() && toElement(this)->hasClass();
 }
 
 inline Node::InsertionNotificationRequest Node::insertedInto(ContainerNode* insertionPoint)
 {
+    ASSERT(!childNeedsStyleInvalidation());
+    ASSERT(!needsStyleInvalidation());
     ASSERT(insertionPoint->inDocument() || isContainerNode());
     if (insertionPoint->inDocument())
         setFlag(InDocumentFlag);
     if (parentOrShadowHostNode()->isInShadowTree())
         setFlag(IsInShadowTreeFlag);
     if (childNeedsDistributionRecalc() && !insertionPoint->childNeedsDistributionRecalc())
         insertionPoint->markAncestorsWithChildNeedsDistributionRecalc();
     return InsertionDone;
 }
 
@@ skipping 47 matching lines @@
     template <> inline bool isElementOfType<const thisType>(const Element& element) { return element.predicate; } \
     DEFINE_NODE_TYPE_CASTS(thisType, predicate)
 
 #define DEFINE_ELEMENT_TYPE_CASTS_WITH_FUNCTION(thisType) \
     template <> inline bool isElementOfType<const thisType>(const Element& element) { return is##thisType(element); } \
     DEFINE_NODE_TYPE_CASTS_WITH_FUNCTION(thisType)
 
 } // namespace
 
 #endif