create promo for debug.

third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc.
  * All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
@@ skipping 1190 matching lines @@
 
 StyleRuleKeyframes* StyleResolver::FindKeyframesRule(
     const Element* element,
     const AtomicString& animation_name) {
   HeapVector<Member<ScopedStyleResolver>, 8> resolvers;
   CollectScopedResolversForHostedShadowTrees(*element, resolvers);
   if (ScopedStyleResolver* scoped_resolver =
           element->GetTreeScope().GetScopedStyleResolver())
     resolvers.push_back(scoped_resolver);
 
+  if (element->IsInShadowTree() &&
+      ToShadowRoot(element->GetTreeScope().RootNode()).GetType() ==
+          ShadowRootType::kUserAgent) {
+    ScopedStyleResolver* scoped_resolver = element->GetDocument().GetScopedStyleResolver();
+    scoped_resolver->AddKeyframeRules(*CSSDefaultStyleSheets::Instance().DefaultStyle());
+    resolvers.push_back(scoped_resolver);
+  }
+
   for (auto& resolver : resolvers) {
     if (StyleRuleKeyframes* keyframes_rule =
             resolver->KeyframeStylesForAnimation(animation_name.Impl()))
       return keyframes_rule;
   }
 
   for (auto& resolver : resolvers)
     resolver->SetHasUnresolvedKeyframesRule();
   return nullptr;
 }
@@ skipping 814 matching lines @@
 
 DEFINE_TRACE(StyleResolver) {
   visitor->Trace(matched_properties_cache_);
   visitor->Trace(selector_filter_);
   visitor->Trace(style_sharing_lists_);
   visitor->Trace(document_);
   visitor->Trace(tracker_);
 }
 
 }  // namespace blink