Make Custom Elements V1 work in HTML imports documents

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

Index: third_party/WebKit/Source/core/dom/custom/CustomElement.cpp
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElement.cpp b/third_party/WebKit/Source/core/dom/custom/CustomElement.cpp
index bab2bec31f979861f122309a32330b8eedf6d6be..57061b3d7e5af5c49d6b11ad9ac13fae50d45391 100644
--- a/third_party/WebKit/Source/core/dom/custom/CustomElement.cpp
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElement.cpp
@@ -27,8 +27,17 @@ CustomElementsRegistry* CustomElement::registry(const Element& element)
 
 CustomElementsRegistry* CustomElement::registry(const Document& document)
 {
-    if (LocalDOMWindow* window = document.domWindow())
-        return window->customElements();
+    if (Document* contextDocument = const_cast<Document&>(document).contextDocument()) {

[dominicc (has gone to gerrit), 2016/07/13 06:12:30]

FYI haraken says in Q4 that Blink will be able to run JavaScript in detached
contexts. What we have today means elements will not run callbacks if their
document is detached. We may need to have elements point to their definitions or
something.

Just a "heads up" that something like this is coming--nothing to do in this
patch.

+        if (LocalDOMWindow* window = contextDocument->domWindow())
+            return window->customElements();
+    }
+    return nullptr;
+}
+
+FrameHost* CustomElement::contextFrameHost(const Element& element)
+{
+    if (Document* contextDocument = element.document().contextDocument())
+        return contextDocument->frameHost();
     return nullptr;
 }
 
@@ -78,7 +87,8 @@ bool CustomElement::isValidName(const AtomicString& name)
 bool CustomElement::shouldCreateCustomElement(Document& document, const AtomicString& localName)
 {
     return RuntimeEnabledFeatures::customElementsV1Enabled()
-        && document.frame() && isValidName(localName);
+        && document.contextDocument() && document.contextDocument()->frame()
+        && isValidName(localName);
 }
 
 bool CustomElement::shouldCreateCustomElement(Document& document, const QualifiedName& tagName)
@@ -176,7 +186,7 @@ void CustomElement::enqueue(Element* element, CustomElementReaction* reaction)
 
     // If the custom element reactions stack is empty, then
     // Add element to the backup element queue.
-    element->document().frameHost()->customElementReactionStack()
+    contextFrameHost(*element)->customElementReactionStack()
         .enqueueToBackupQueue(element, reaction);
 }