Creating customized built-in elements without relevant definitions registered first shouldn't throw NotFoundError;

per spec change: https://github.com/w3c/webcomponents/issues/608

Tag UXP Issue #1344

dom/base/nsDocument.cpp

@@ -5395,14 +5395,6 @@ nsDocument::CreateElement(const nsAString& aTagName,
   }
 
   const nsString* is = nullptr;
-  if (aOptions.IsElementCreationOptions()) {
-    // Throw NotFoundError if 'is' is not-null and definition is null
-    is = CheckCustomElementName(aOptions.GetAsElementCreationOptions(),
-      needsLowercase ? lcTagName : aTagName, mDefaultElementType, rv);
-    if (rv.Failed()) {
-      return nullptr;
-    }
-  }
 
   RefPtr<Element> elem = CreateElem(
     needsLowercase ? lcTagName : aTagName, nullptr, mDefaultElementType, is);
@@ -5443,14 +5435,6 @@ nsDocument::CreateElementNS(const nsAString& aNamespaceURI,
   }
 
   const nsString* is = nullptr;
-  if (aOptions.IsElementCreationOptions()) {
-    // Throw NotFoundError if 'is' is not-null and definition is null
-    is = CheckCustomElementName(aOptions.GetAsElementCreationOptions(),
-                                aQualifiedName, nodeInfo->NamespaceID(), rv);
-    if (rv.Failed()) {
-      return nullptr;
-    }
-  }
 
   nsCOMPtr<Element> element;
   rv = NS_NewElement(getter_AddRefs(element), nodeInfo.forget(),
@@ -12757,30 +12741,6 @@ nsIDocument::UpdateStyleBackendType()
 #endif
 }
 
-const nsString*
-nsDocument::CheckCustomElementName(const ElementCreationOptions& aOptions,
-                                   const nsAString& aLocalName,
-                                   uint32_t aNamespaceID,
-                                   ErrorResult& rv)
-{
-  // only check aOptions if 'is' is passed and the webcomponents preference
-  // is enabled
-  if (!aOptions.mIs.WasPassed() ||
-      !CustomElementRegistry::IsCustomElementEnabled()) {
-      return nullptr;
-  }
-
-  const nsString* is = &aOptions.mIs.Value();
-
-  // Throw NotFoundError if 'is' is not-null and definition is null
-  if (!nsContentUtils::LookupCustomElementDefinition(this, aLocalName,
-                                                     aNamespaceID, is)) {
-      rv.Throw(NS_ERROR_DOM_NOT_FOUND_ERR);
-  }
-
-  return is;
-}
-
 Selection*
 nsIDocument::GetSelection(ErrorResult& aRv)
 {

dom/base/nsDocument.h

@@ -1388,20 +1388,6 @@ protected:
 private:
   static bool CustomElementConstructor(JSContext* aCx, unsigned aArgc, JS::Value* aVp);
 
-  /**
-   * Check if the passed custom element name, aOptions.mIs, is a registered
-   * custom element type or not, then return the custom element name for future
-   * usage.
-   *
-   * If there is no existing custom element definition for this name, throw a
-   * NotFoundError.
-   */
-  const nsString* CheckCustomElementName(
-    const mozilla::dom::ElementCreationOptions& aOptions,
-    const nsAString& aLocalName,
-    uint32_t aNamespaceID,
-    ErrorResult& rv);
-
 public:
   virtual already_AddRefed<mozilla::dom::CustomElementRegistry>
     GetCustomElementRegistry() override;

dom/tests/mochitest/webcomponents/test_document_register.html

@@ -103,52 +103,12 @@ function startTest() {
   is(extendedButton.getAttribute("is"), "x-extended-button", "The |is| attribute of the created element should be the extended type.");
   is(extendedButton.type, "submit", "Created element should be a button with type of \"submit\"");
 
-  // document.createElementNS with different namespace than definition.
-  try {
-    var svgButton = document.createElementNS("http://www.w3.org/2000/svg", "button", {is: "x-extended-button"});
-    ok(false, "An exception should've been thrown");
-  } catch(err) {
-    is(err.name, "NotFoundError", "A NotFoundError exception should've been thrown");
-  }
-
-  // document.createElementNS with no namespace.
-  try {
-    var noNamespaceButton = document.createElementNS("", "button", {is: "x-extended-button"});
-    ok(false, "An exception should've been thrown");
-  } catch(err) {
-    is(err.name, "NotFoundError", "A NotFoundError exception should've been thrown");
-  }
-
-  // document.createElement with non-existant extended type.
-  try {
-    var normalButton = document.createElement("button", {is: "x-non-existant"});
-    ok(false, "An exception should've been thrown");
-  } catch(err) {
-    is(err.name, "NotFoundError", "A NotFoundError exception should've been thrown");
-  }
-
-  // document.createElement with exteneded type that does not match with local name of element.
-  try {
-    var normalDiv = document.createElement("div", {is: "x-extended-button"});
-    ok(false, "An exception should've been thrown");
-  } catch(err) {
-    is(err.name, "NotFoundError", "A NotFoundError exception should've been thrown");
-  }
-
   // Custom element constructor.
   var constructedButton = new buttonConstructor();
   is(constructedButton.tagName, "BUTTON", "Created element should have local name of BUTTON");
   is(constructedButton.__proto__, extendedProto, "Created element should have the prototype of the extended type.");
   is(constructedButton.getAttribute("is"), "x-extended-button", "The |is| attribute of the created element should be the extended type.");
 
-  // document.createElement with different namespace than definition for extended element.
-  try {
-    var htmlText = document.createElement("text", {is: "x-extended-text"});
-    ok(false, "An exception should've been thrown");
-  } catch(err) {
-    is(err.name, "NotFoundError", "A NotFoundError exception should've been thrown");
-  }
-
   // Try creating an element with a custom element name, but not in the html namespace.
   var htmlNamespaceProto = Object.create(HTMLElement.prototype);
   document.registerElement("x-in-html-namespace", { prototype: htmlNamespaceProto });