Add assert that updateLayoutTree clears dirty bits.

Source/core/dom/Element.cpp

 /*
  * 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)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1440 matching lines @@
     // We've already been through detach when doing an attach, but we might
     // need to clear any state that's been added since then.
     if (hasRareData() && styleChangeType() == NeedsReattachStyleChange) {
         ElementRareData* data = elementRareData();
         data->clearComputedStyle();
     }
 
     if (!isActiveInsertionPoint(*this))
         LayoutTreeBuilderForElement(*this, context.resolvedStyle).createLayoutObjectIfNeeded();
 
+    if (hasRareData() && !layoutObject()) {
+        if (ElementAnimations* elementAnimations = elementRareData()->elementAnimations()) {
+            elementAnimations->cssAnimations().cancel();
+            elementAnimations->setAnimationStyleChange(false);
+        }
+    }
+
     addCallbackSelectors();
 
     StyleResolverParentScope parentScope(*this);
 
     createPseudoElementIfNeeded(BEFORE);
 
     // When a shadow root exists, it does the work of attaching the children.
     if (ElementShadow* shadow = this->shadow())
         shadow->attach(context);
 
     ContainerNode::attach(context);
 
     createPseudoElementIfNeeded(AFTER);
     createPseudoElementIfNeeded(BACKDROP);
 
     // We create the first-letter element after the :before, :after and
     // children are attached because the first letter text could come
     // from any of them.
     createPseudoElementIfNeeded(FIRST_LETTER);
-
-    if (hasRareData() && !layoutObject()) {
-        if (ElementAnimations* elementAnimations = elementRareData()->elementAnimations()) {
-            elementAnimations->cssAnimations().cancel();
-            elementAnimations->setAnimationStyleChange(false);
-        }
-    }
 }
 
 void Element::detach(const AttachContext& context)
 {
     HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
     cancelFocusAppearanceUpdate();
     removeCallbackSelectors();
     if (hasRareData()) {
         ElementRareData* data = elementRareData();
         data->clearPseudoElements();
@@ skipping 1973 matching lines @@
 {
 #if ENABLE(OILPAN)
     if (hasRareData())
         visitor->trace(elementRareData());
     visitor->trace(m_elementData);
 #endif
     ContainerNode::trace(visitor);
 }
 
 } // namespace blink