Revert of Remove scoped styles.

Source/core/dom/shadow/ShadowRoot.cpp

 /*
  * Copyright (C) 2011 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 201 matching lines @@
 
     if (InsertionPoint* point = shadowInsertionPointOfYoungerShadowRoot()) {
         if (ShadowRoot* root = point->containingShadowRoot())
             root->owner()->setNeedsDistributionRecalc();
     }
 }
 
 void ShadowRoot::registerScopedHTMLStyleChild()
 {
     ++m_numberOfStyles;
+    setHasScopedHTMLStyleChild(true);
 }
 
 void ShadowRoot::unregisterScopedHTMLStyleChild()
 {
-    ASSERT(m_numberOfStyles > 0);
+    ASSERT(hasScopedHTMLStyleChild() && m_numberOfStyles > 0);
     --m_numberOfStyles;
+    setHasScopedHTMLStyleChild(m_numberOfStyles > 0);
 }
 
 ShadowRootRareData* ShadowRoot::ensureShadowRootRareData()
 {
     if (m_shadowRootRareData)
         return m_shadowRootRareData.get();
 
     m_shadowRootRareData = adoptPtrWillBeNoop(new ShadowRootRareData);
     return m_shadowRootRareData.get();
 }
@@ skipping 99 matching lines @@
 void ShadowRoot::trace(Visitor* visitor)
 {
     visitor->trace(m_prev);
     visitor->trace(m_next);
     visitor->trace(m_shadowRootRareData);
     TreeScope::trace(visitor);
     DocumentFragment::trace(visitor);
 }
 
 }