Track reasons for |Node::SetNeedsStyleRecalc|

Source/core/dom/shadow/ElementShadow.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 236 matching lines @@
 
 const DestinationInsertionPoints* ElementShadow::destinationInsertionPointsFor(const Node* key) const
 {
     ASSERT(key && !key->document().childNeedsDistributionRecalc());
     NodeToDestinationInsertionPoints::const_iterator it = m_nodeToInsertionPoints.find(key);
     return it == m_nodeToInsertionPoints.end() ? 0: &it->value;
 }
 
 void ElementShadow::distribute()
 {
-    host()->setNeedsStyleRecalc(SubtreeStyleChange);
+    host()->setNeedsStyleRecalc(StyleRecalcDueToShadow, SubtreeStyleChange);
     WillBeHeapVector<RawPtrWillBeMember<HTMLShadowElement>, 32> shadowInsertionPoints;
     DistributionPool pool(*host());
 
     for (ShadowRoot* root = youngestShadowRoot(); root; root = root->olderShadowRoot()) {
         HTMLShadowElement* shadowInsertionPoint = 0;
         const WillBeHeapVector<RefPtrWillBeMember<InsertionPoint> >& insertionPoints = root->descendantInsertionPoints();
         for (size_t i = 0; i < insertionPoints.size(); ++i) {
             InsertionPoint* point = insertionPoints[i].get();
             if (!point->isActive())
                 continue;
@@ skipping 93 matching lines @@
     visitor->trace(m_nodeToInsertionPoints);
     visitor->trace(m_selectFeatures);
     // Shadow roots are linked with previous and next pointers which are traced.
     // It is therefore enough to trace one of the shadow roots here and the
     // rest will be traced from there.
     visitor->trace(m_shadowRoots.head());
 #endif
 }
 
 } // namespace