Implement the Custom Elements :unresolved pseudoclass

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index f18ac2b05375b96c045b293df9af459255907fc3..ec7f353117253b0be46c7b06553960d1e3163c44 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -213,6 +213,10 @@ Element::~Element()
         data->clearShadow();
     }
 
+    if (isCustomElement() && document() && document()->registry()) {
+        document()->registry()->customElementWasDestroyed(this);
+    }
+
     if (hasSyntheticAttrChildNodes())
         detachAllAttrNodesFromElement();
 
@@ -2202,6 +2206,11 @@ bool Element::isInCanvasSubtree() const
     return hasRareData() && elementRareData()->isInCanvasSubtree();
 }
 
+bool Element::isUnresolvedCustomElement()
+{
+    return isCustomElement() && document()->registry()->isUnresolved(this);
+}
+
 AtomicString Element::computeInheritedLanguage() const
 {
     const Node* n = this;