Share Custom Element registration contexts between related documents.

Source/core/dom/DOMImplementation.cpp

Index: Source/core/dom/DOMImplementation.cpp
diff --git a/Source/core/dom/DOMImplementation.cpp b/Source/core/dom/DOMImplementation.cpp
index 6cb05e90f29c4d2bfcab06a0c88d911845ae074c..deb6fe232a544c8e3487174a515153cea6fb7339 100644
--- a/Source/core/dom/DOMImplementation.cpp
+++ b/Source/core/dom/DOMImplementation.cpp
@@ -31,6 +31,7 @@
 #include "core/css/MediaList.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/dom/ContextFeatures.h"
+#include "core/dom/CustomElementRegistrationContextualizer.h"
 #include "core/dom/DocumentType.h"
 #include "core/dom/Element.h"
 #include "core/dom/ExceptionCode.h"
@@ -263,6 +264,7 @@ PassRefPtr<Document> DOMImplementation::createDocument(const String& namespaceUR
 
     doc->setSecurityOrigin(m_document->securityOrigin());
     doc->setContextFeatures(m_document->contextFeatures());
+    CustomElementRegistrationContextualizer::didCreateRelatedDocument(m_document->registrationContext(), CustomElementRegistrationContextualizer::DOMImplementation_createDocument, doc.get());
 
     RefPtr<Node> documentElement;
     if (!qualifiedName.isEmpty()) {
@@ -379,6 +381,7 @@ PassRefPtr<HTMLDocument> DOMImplementation::createHTMLDocument(const String& tit
         d->setTitle(title);
     d->setSecurityOrigin(m_document->securityOrigin());
     d->setContextFeatures(m_document->contextFeatures());
+    CustomElementRegistrationContextualizer::didCreateRelatedDocument(m_document->registrationContext(), CustomElementRegistrationContextualizer::DOMImplementation_createDocument, d.get());
     return d.release();
 }