fix(radio): Register selection controller after update complete.

PiperOrigin-RevId: 332112768

Author: abhiomkar

packages/radio/mwc-radio-base.ts

@@ -77,6 +77,7 @@ export class RadioBase extends FormElement {
     this.requestUpdate('checked', oldValue);
 
     // useful when unchecks self and wrapping element needs to synchronize
+    // TODO(b/168543810): Remove triggering event on programmatic API call.
     this.dispatchEvent(new Event('checked', {bubbles: true, composed: true}));
   }
 

packages/radio/single-selection-controller.ts

@@ -266,7 +266,12 @@ export class SingleSelectionController {
    * @param element Element to register. Registers in set of `element.name`.
    */
   register(element: CheckableElement) {
-    const set = this.getSet(element.name);
+    // TODO(b/168546148): Remove accessing 'name' via getAttribute() when new
+    // base class is created without single selection controller. Component
+    // maybe booted up after it is connected to DOM in which case properties
+    // (including `name`) are not updated yet.
+    const name = element.name || element.getAttribute('name') || '';
+    const set = this.getSet(name);
     set.set.add(element);
     set.ordered = null;
   }