custom-elements: Handle V0 type extension as close to element creation as possible.

Move V0 type extension handling in Element::
AttributeChangedFromParserOrByCloning() to its callsites close to
element creation.

* HTMLConstructionSite:
  Move 'is' attribute lookup from LookUpCustomElementDefinition() to
  CreateElement() in order to avoid looking up 'is' again.

* XMLDocumentParser:
  Convert libxml attributes to blink::Attribute before element creation
  to find 'is' attribute easily.

This CL has no behavior changes, and is a preparation to consolidate
V0 type extension handling and element creation.

Bug: 808302, 808311, 807871
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ibb4254720f1bed8b92e878fa7b29c986bfa1f87d
Reviewed-on: https://chromium-review.googlesource.com/898685Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534035}

third_party/WebKit/Source/core/dom/Document.cpp

@@ -1291,6 +1291,11 @@ Node* Document::importNode(Node* imported_node,
       }
       Element* new_element =
           createElement(old_element->TagQName(), kCreatedByImportNode);
+      const AtomicString& is = old_element->FastGetAttribute(HTMLNames::isAttr);
+      if (!is.IsNull() &&
+          !V0CustomElement::IsValidName(new_element->localName()))
+        V0CustomElementRegistrationContext::SetTypeExtension(new_element, is);
+      // TODO(tkent): Handle V1 custom built-in elements. crbug.com/807871
 
       new_element->CloneDataFromElement(*old_element);
 

third_party/WebKit/Source/core/dom/Element.cpp

@@ -280,7 +280,12 @@ Element* Element::CloneElementWithoutChildren() {
 }
 
 Element* Element::CloneElementWithoutAttributesAndChildren() {
-  return GetDocument().createElement(TagQName(), kCreatedByCloneNode);
+  auto* element = GetDocument().createElement(TagQName(), kCreatedByCloneNode);
+  const AtomicString& is = FastGetAttribute(HTMLNames::isAttr);
+  if (!is.IsNull() && !V0CustomElement::IsValidName(element->localName()))
+    V0CustomElementRegistrationContext::SetTypeExtension(element, is);
+  // TODO(tkent): Handle V1 custom built-in elements. crbug.com/807871
+  return element;
 }
 
 Attr* Element::DetachAttribute(size_t index) {
@@ -1501,12 +1506,11 @@ const QualifiedName& Element::SubResourceAttributeName() const {
   return QualifiedName::Null();
 }
 
+// TODO(tkent): Remove this function, and call AttributeChanged directly.
 inline void Element::AttributeChangedFromParserOrByCloning(
     const QualifiedName& name,
     const AtomicString& new_value,
     AttributeModificationReason reason) {
-  if (name == isAttr && !V0CustomElement::IsValidName(localName()))
-    V0CustomElementRegistrationContext::SetTypeExtension(this, new_value);
   AttributeChanged(
       AttributeModificationParams(name, g_null_atom, new_value, reason));
 }

third_party/WebKit/Source/core/html/HTMLScriptElement.cpp

@@ -225,8 +225,13 @@ void HTMLScriptElement::SetScriptElementForBinding(
 }
 
 Element* HTMLScriptElement::CloneElementWithoutAttributesAndChildren() {
-  return new HTMLScriptElement(GetDocument(), false, loader_->AlreadyStarted(),
-                               false);
+  auto* element = new HTMLScriptElement(GetDocument(), false,
+                                        loader_->AlreadyStarted(), false);
+  const AtomicString& is = FastGetAttribute(HTMLNames::isAttr);
+  if (!is.IsNull() && !V0CustomElement::IsValidName(element->localName()))
+    V0CustomElementRegistrationContext::SetTypeExtension(element, is);
+  // TODO(tkent): Handle V1 custom built-in elements. crbug.com/807871
+  return element;
 }
 
 void HTMLScriptElement::Trace(blink::Visitor* visitor) {

third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.cpp

@@ -412,6 +412,12 @@ void HTMLConstructionSite::InsertHTMLHtmlStartTagBeforeHTML(
     AtomicHTMLToken* token) {
   DCHECK(document_);
   HTMLHtmlElement* element = HTMLHtmlElement::Create(*document_);
+  if (const Attribute* is_attribute =
+          token->GetAttributeItem(HTMLNames::isAttr)) {
+    V0CustomElementRegistrationContext::SetTypeExtension(element,
+                                                         is_attribute->Value());
+  }
+  // TODO(tkent): Handle V1 custom built-in element. crbug.com/808311
   SetAttributes(element, token, parser_content_policy_);
   AttachLater(attachment_root_, element);
   open_elements_.PushHTMLHtmlElement(HTMLStackItem::Create(element, token));
@@ -736,6 +742,12 @@ void HTMLConstructionSite::InsertScriptElement(AtomicHTMLToken* token) {
   HTMLScriptElement* element =
       HTMLScriptElement::Create(OwnerDocumentForCurrentNode(), parser_inserted,
                                 already_started, created_during_document_write);
+  if (const Attribute* is_attribute =
+          token->GetAttributeItem(HTMLNames::isAttr)) {
+    V0CustomElementRegistrationContext::SetTypeExtension(element,
+                                                         is_attribute->Value());
+  }
+  // TODO(tkent): Handle V1 custom built-in element. crbug.com/808311
   SetAttributes(element, token, parser_content_policy_);
   if (ScriptingContentIsAllowed(parser_content_policy_))
     AttachLater(CurrentNode(), element);
@@ -837,7 +849,8 @@ inline Document& HTMLConstructionSite::OwnerDocumentForCurrentNode() {
 // https://html.spec.whatwg.org/#look-up-a-custom-element-definition
 CustomElementDefinition* HTMLConstructionSite::LookUpCustomElementDefinition(
     Document& document,
-    AtomicHTMLToken* token) {
+    AtomicHTMLToken* token,
+    const AtomicString& is) {
   // "2. If document does not have a browsing context, return null."
   LocalDOMWindow* window = document.ExecutingWindow();
   if (!window)
@@ -850,8 +863,7 @@ CustomElementDefinition* HTMLConstructionSite::LookUpCustomElementDefinition(
     return nullptr;
 
   const AtomicString& local_name = token->GetName();
-  const Attribute* is_attribute = token->GetAttributeItem(HTMLNames::isAttr);
-  const AtomicString& name = is_attribute ? is_attribute->Value() : local_name;
+  const AtomicString& name = !is.IsNull() ? is : local_name;
   CustomElementDescriptor descriptor(name, local_name);
 
   // 4.-6.
@@ -869,8 +881,10 @@ Element* HTMLConstructionSite::CreateElement(
   // "2. Let local name be the tag name of the token."
   QualifiedName tag_name(g_null_atom, token->GetName(), namespace_uri);
   // "3. Let is be the value of the "is" attribute in the given token ..." etc.
+  const Attribute* is_attribute = token->GetAttributeItem(HTMLNames::isAttr);
+  const AtomicString& is = is_attribute ? is_attribute->Value() : g_null_atom;
   // "4. Let definition be the result of looking up a custom element ..." etc.
-  auto* definition = LookUpCustomElementDefinition(document, token);
+  auto* definition = LookUpCustomElementDefinition(document, token, is);
   // "5. If definition is non-null and the parser was not originally created
   // for the HTML fragment parsing algorithm, then let will execute script
   // be true."
@@ -914,6 +928,8 @@ Element* HTMLConstructionSite::CreateElement(
                                                GetCreateElementFlags());
     } else {
       element = document.createElement(tag_name, GetCreateElementFlags());
+      if (!is.IsNull() && !V0CustomElement::IsValidName(tag_name.LocalName()))
+        V0CustomElementRegistrationContext::SetTypeExtension(element, is);
     }
     // Definition for the created element does not exist here and it cannot be
     // custom or failed.

third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h

@@ -262,8 +262,10 @@ class HTMLConstructionSite final {
   void ExecuteTask(HTMLConstructionSiteTask&);
   void QueueTask(const HTMLConstructionSiteTask&);
 
-  CustomElementDefinition* LookUpCustomElementDefinition(Document&,
-                                                         AtomicHTMLToken*);
+  CustomElementDefinition* LookUpCustomElementDefinition(
+      Document&,
+      AtomicHTMLToken*,
+      const AtomicString& is);
 
   HTMLParserReentryPermit* reentry_permit_;
   Member<Document> document_;

third_party/WebKit/Source/core/svg/SVGScriptElement.cpp

@@ -148,7 +148,12 @@ Document& SVGScriptElement::GetDocument() const {
 }
 
 Element* SVGScriptElement::CloneElementWithoutAttributesAndChildren() {
-  return new SVGScriptElement(GetDocument(), false, loader_->AlreadyStarted());
+  auto* element =
+      new SVGScriptElement(GetDocument(), false, loader_->AlreadyStarted());
+  const AtomicString& is = FastGetAttribute(HTMLNames::isAttr);
+  if (!is.IsNull() && !V0CustomElement::IsValidName(element->localName()))
+    V0CustomElementRegistrationContext::SetTypeExtension(element, is);
+  return element;
 }
 
 void SVGScriptElement::DispatchLoadEvent() {

third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp

@@ -951,26 +951,36 @@ void XMLDocumentParser::StartElementNs(const AtomicString& local_name,
   bool is_first_element = !saw_first_element_;
   saw_first_element_ = true;
 
-  QualifiedName q_name(prefix, local_name, adjusted_uri);
-  Element* new_element =
-      current_node_->GetDocument().createElement(q_name, kCreatedByParser);
-  if (!new_element) {
-    StopParsing();
-    return;
-  }
-
   Vector<Attribute> prefixed_attributes;
   DummyExceptionStateForTesting exception_state;
   HandleNamespaceAttributes(prefixed_attributes, libxml_namespaces,
                             nb_namespaces, exception_state);
   if (exception_state.HadException()) {
-    SetAttributes(new_element, prefixed_attributes, GetParserContentPolicy());
     StopParsing();
     return;
   }
 
   HandleElementAttributes(prefixed_attributes, libxml_attributes, nb_attributes,
                           prefix_to_namespace_map_, exception_state);
+
+  QualifiedName q_name(prefix, local_name, adjusted_uri);
+  Element* new_element =
+      current_node_->GetDocument().createElement(q_name, kCreatedByParser);
+  if (!new_element) {
+    StopParsing();
+    return;
+  }
+  for (const auto& attr : prefixed_attributes) {
+    if (attr.GetName() == isAttr) {
+      if (!V0CustomElement::IsValidName(local_name)) {
+        V0CustomElementRegistrationContext::SetTypeExtension(new_element,
+                                                             attr.Value());
+      }
+      break;
+    }
+  }
+  // TODO(tkent): Support V1 custom built-in elements. crbug.com/808302
+
   SetAttributes(new_element, prefixed_attributes, GetParserContentPolicy());
   if (exception_state.HadException()) {
     StopParsing();