diff --git a/source b/source index 2488e8f79bb..fa5be21b341 100644 --- a/source +++ b/source @@ -66390,6 +66390,8 @@ document.body.append(parent); 
[Exposed=Window]
 interface CustomElementRegistry {
+  constructor();
+
   [CEReactions] undefined define(DOMString name, CustomElementConstructor constructor, optional ElementDefinitionOptions options = {});
   (CustomElementConstructor or undefined) get(DOMString name);
   Promise<CustomElementConstructor> whenDefined(DOMString name);
@@ -66428,7 +66430,6 @@ dictionary ElementDefinitionOptions {
    
Defines a new custom element, mapping the given name to the given constructor as
    an autonomous custom element.

 
-
    
window . customElements . define(name, constructor,
    { extends: baseLocalName })

@@ -66464,8 +66465,38 @@ dictionary ElementDefinitionOptions {
    connected.
   
 
+  
New instances of CustomElementRegistry can be defined and attached to a
+  ShadowRoot through the registry option from attachShadow(). Those instances are independent of the
+  instance available at window.customElements, as
+  the latter is attached to the
+  associated Document.

+
+  

+    
registry = new CustomElementRegistry()

+
+    
Defines a new Registry that can map an
+    independent set of custom elements, which is
+    not associated yet to any ShadowRoot.

+
+    
registry . define(name,
+      constructor)

+
+    
Defines a new custom element within the given registry,
+    mapping the given name to the given constructor as an autonomous custom element.
+    

+  

+
+  
When the CustomElementRegistry()
+  constructor is invoked, the user agent must run the following steps:

+
+  
    
+    
  1. Let registry be a new CustomElementRegistry object.
+    
  2. Return registry.
+  

+
   
Element definition is a process of adding a custom element definition
-  to the CustomElementRegistry. This is accomplished by the CustomElementRegistry object. This is accomplished by the define() method. When invoked,
   the define(name,
   constructor, options) method must run these steps:

@@ -66479,11 +66510,11 @@ dictionary ElementDefinitionOptions {
    
  • If name is not a valid custom element name, then throw a
    "SyntaxError" DOMException.
    • 
 
-   
  • If this CustomElementRegistry contains an entry with 
    If this CustomElementRegistry object contains an entry with name name, then throw a
    "NotSupportedError" DOMException.
    • 
 
-   
  • If this CustomElementRegistry contains an entry with 
    If this CustomElementRegistry object contains an entry with constructor constructor,
    then throw a "NotSupportedError" DOMException.
    • 
 
@@ -66508,11 +66539,12 @@ dictionary ElementDefinitionOptions {
     
    
 
-   
  • If this CustomElementRegistry's element definition is running
-   flag is set, then throw a "NotSupportedError" DOMException.
    • 
+   
  • If this CustomElementRegistry's element definition is
+   running flag is set, then throw a "NotSupportedError"
+   DOMException.
    • 
 
-   
  • Set this CustomElementRegistry's element definition is running
-   flag.
    • 
+   
  • Set this CustomElementRegistry's element definition is
+   running flag.
    • 
 
    
  • Let formAssociated be false.
    • 
 
@@ -66642,11 +66674,11 @@ dictionary ElementDefinitionOptions {
    data-x="concept-custom-element-definition-disable-shadow">disable shadow
    disableShadow.
    
 
-   
  • Add definition to this CustomElementRegistry.
    • 
+   
  • Add definition to this CustomElementRegistry object.
    • 
 
-   
  • Let document be this CustomElementRegistry's relevant global
-   object's associated
-   Document.
    • 
+   
  • Let document be this CustomElementRegistry's relevant
+   global object's associated DocumentOrShadowRoot.
    • 
 
    
  • Let upgrade candidates be all elements that are shadow-including descendants of document, whose namespace
@@ -66677,6 +66709,12 @@ dictionary ElementDefinitionOptions {
    
    • 
   
 
+  
    define and the other
+  methods for CustomElementRegistry will operate on the definitions set for the
+  respective object such as the customElements or
+  other registries created with
+  new CustomElementRegistry().
    
+
   
    When invoked, the get(name) method must run these
   steps:
    
@@ -125034,6 +125072,7 @@ INSERT INTERFACES HERE
   Leif Halvard Silli,
   Leif Kornstaedt,
   Lenny Domnitser,
+  Leo Balter,
   Leonard Rosenthol,
   Leons Petrazickis,
   Lobotom Dysmon,