Support Style Sharing for Shadow DOM V1

third_party/WebKit/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)
  *
@@ skipping 4005 matching lines @@
   // and no siblings or cousins will have the same state. There's also only one
   // :focus element per scope so we don't need to attempt to share.
   if (isUserActionElement())
     return false;
   if (!parentOrShadowHostElement()->childrenSupportStyleSharing())
     return false;
   if (this == document().cssTarget())
     return false;
   if (isHTMLElement() && toHTMLElement(this)->hasDirectionAuto())
     return false;
-  // TODO(kochi): This prevents any slotted elements from sharing styles.
-  // Investigate cases where we share styles to optimize styling performance.
-  if (isChildOfV1ShadowHost())
-    return false;
   if (hasAnimations())
     return false;
   if (Fullscreen::isFullscreenElement(*this))
     return false;
   return true;
 }
 
 void Element::logAddElementIfIsolatedWorldAndInDocument(
     const char element[],
     const QualifiedName& attr1) {
@@ skipping 70 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (hasRareData()) {
     visitor->traceWrappers(elementRareData());
   }
   ContainerNode::traceWrappers(visitor);
 }
 
 }  // namespace blink