Fix upgrading built-in custom elements

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc.
  * All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
@@ skipping 1429 matching lines @@
 }
 
 const QualifiedName& Element::SubResourceAttributeName() const {
   return QualifiedName::Null();
 }
 
 inline void Element::AttributeChangedFromParserOrByCloning(
     const QualifiedName& name,
     const AtomicString& new_value,
     AttributeModificationReason reason) {
-  if (name == isAttr)
+  if (name == isAttr) {
     V0CustomElementRegistrationContext::SetTypeExtension(this, new_value);
+    if (RuntimeEnabledFeatures::CustomElementsBuiltinEnabled() &&

[dominicc (has gone to gerrit), 2017/06/26 03:03:19]

I thought the timing of processing these was different for customized built-in
elements in V1. Can you put a link to the spec algorithm and note which step
does this?

[Anton Obzhirov, 2017/06/27 19:19:00]

Well it is wrong place to set the state, you are right.

The state is supposed to be set to 'undefined' for new element
if 'is' is not null and definition is null.
See https://dom.spec.whatwg.org/#concept-create-element,
7.3. If namespace is the HTML namespace, and either localName is a valid custom
element name or is is non-null, then set result’s custom element state to
"undefined".

So I think the problem is really in HTMLElementFactory::createHTMLElement so it
doesn't create built-in element through CustomElement::CreateCustomElementSync
API. I will make the changes.

+        GetCustomElementState() == CustomElementState::kUncustomized) {
+      SetCustomElementState(CustomElementState::kUndefined);
+    }
+  }
+
   AttributeChanged(
       AttributeModificationParams(name, g_null_atom, new_value, reason));
 }
 
 template <typename CharacterType>
 static inline ClassStringContent ClassStringHasClassName(
     const CharacterType* characters,
     unsigned length) {
   DCHECK_GT(length, 0u);
 
@@ skipping 2949 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (HasRareData()) {
     visitor->TraceWrappers(GetElementRareData());
   }
   ContainerNode::TraceWrappers(visitor);
 }
 
 }  // namespace blink