blink/css: Read animation keyframe rules in UA sheets for shadow DOM.

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 1196 matching lines @@
   if (ScopedStyleResolver* scoped_resolver =
           element->GetTreeScope().GetScopedStyleResolver())
     resolvers.push_back(scoped_resolver);
 
   for (auto& resolver : resolvers) {
     if (StyleRuleKeyframes* keyframes_rule =
             resolver->KeyframeStylesForAnimation(animation_name.Impl()))
       return keyframes_rule;
   }
 
+  // This is a workaround for crbug.com/724975. Since the keyframe rules from
+  // UA style sheets are not available in the resolvers, read those rules
+  // directly here.
+  if (element->IsInShadowTree() &&
+      ToShadowRoot(element->GetTreeScope().RootNode()).GetType() ==
+          ShadowRootType::kUserAgent) {
+    const auto& keyframe_rules =
+        CSSDefaultStyleSheets::Instance().DefaultStyle()->KeyframesRules();
+    for (const auto& rule : keyframe_rules) {
+      if (rule->GetName() == animation_name)
+        return rule;
+    }
+  }
+
   for (auto& resolver : resolvers)
     resolver->SetHasUnresolvedKeyframesRule();
   return nullptr;
 }
 
 template <CSSPropertyPriority priority>
 void StyleResolver::ApplyAnimatedProperties(
     StyleResolverState& state,
     const ActiveInterpolationsMap& active_interpolations_map) {
   // TODO(alancutter): Don't apply presentation attribute animations here,
@@ skipping 808 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