Fix -webkit-* pseudo cannot match CSS animation name

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index 6a3b2ac47f325aae8c9a7622a86f31013bde7b99..3a7f8670bc13f83f7537c17cb3eaf2d2120d5d53 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -992,6 +992,9 @@ StyleRuleKeyframes* StyleResolver::findKeyframesRule(const Element* element, con
     if (ScopedStyleResolver* scopedResolver = element->treeScope().scopedStyleResolver())
         resolvers.append(scopedResolver);
 
+    if (element->isInShadowTree() && toShadowRoot(element->treeScope().rootNode()).type() == ShadowRoot::UserAgentShadowRoot)
+        resolvers.append(element->document().scopedStyleResolver());
+
     for (size_t i = 0; i < resolvers.size(); ++i) {
         if (StyleRuleKeyframes* keyframesRule = resolvers[i]->keyframeStylesForAnimation(animationName.impl()))
             return keyframesRule;