Make custom elements work in HTML imports

third_party/WebKit/Source/core/dom/custom/CustomElement.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/custom/CustomElement.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/QualifiedName.h"
 #include "core/dom/custom/CEReactionsScope.h"
 #include "core/dom/custom/CustomElementDefinition.h"
 #include "core/dom/custom/CustomElementReactionStack.h"
 #include "core/dom/custom/CustomElementsRegistry.h"
 #include "core/dom/custom/V0CustomElement.h"
 #include "core/dom/custom/V0CustomElementRegistrationContext.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/HTMLUnknownElement.h"
 #include "platform/text/Character.h"
 #include "wtf/text/AtomicStringHash.h"
 
 namespace blink {
 
 CustomElementsRegistry* CustomElement::registry(const Element& element)
 {
     return registry(element.document());
 }
+
 CustomElementsRegistry* CustomElement::registry(const Document& document)
 {
-    if (LocalDOMWindow* window = document.domWindow())
-        return window->customElements();
+    if (Document* contextDocument = const_cast<Document&>(document).contextDocument()) {
+        if (LocalDOMWindow* window = contextDocument->domWindow())
+            return window->customElements();
+    }
     return nullptr;
 }
 
 static CustomElementDefinition* definitionForElementWithoutCheck(const Element& element)
 {
     DCHECK_EQ(element.getCustomElementState(), CustomElementState::Custom);
     return element.customElementDefinition();
 }
 
 CustomElementDefinition* CustomElement::definitionForElement(const Element* element)
@@ skipping 33 matching lines @@
         "font-face-format",
         "font-face-name",
         "missing-glyph",
     }));
     return !hyphenContainingElementNames.contains(name);
 }
 
 bool CustomElement::shouldCreateCustomElement(Document& document, const AtomicString& localName)
 {
     return RuntimeEnabledFeatures::customElementsV1Enabled()
+        && document.contextDocument() && document.contextDocument()->frame()
         && isValidName(localName);
 }
 
 bool CustomElement::shouldCreateCustomElement(Document& document, const QualifiedName& tagName)
 {
     return shouldCreateCustomElement(document, tagName.localName())
         && tagName.namespaceURI() == HTMLNames::xhtmlNamespaceURI;
 }
 
 static CustomElementDefinition* definitionForName(const Document& document, const QualifiedName& name)
@@ skipping 146 matching lines @@
     CustomElementsRegistry* registry = CustomElement::registry(*element);
     if (!registry)
         return;
     if (CustomElementDefinition* definition = registry->definitionForName(element->localName()))
         definition->enqueueUpgradeReaction(element);
     else
         registry->addCandidate(element);
 }
 
 } // namespace blink