MD-Settings A11y: Disable radio list if all options are disabled.

third_party/polymer/v1_0/components-chromium/paper-radio-group/paper-radio-group-extracted.js

 Polymer({
     is: 'paper-radio-group',
 
     behaviors: [
       Polymer.IronMenubarBehavior
     ],
 
     hostAttributes: {
       role: 'radiogroup',
-      tabindex: 0
     },
 
     properties: {
       /**
        * Fired when the radio group selection changes.
        *
        * @event paper-radio-group-changed
        */
 
       /**
@@ skipping 19 matching lines @@
         type: String,
         value: 'paper-radio-button'
       },
 
       /**
        * If true, radio-buttons can be deselected
        */
       allowEmptySelection: {
         type: Boolean,
         value: false
-      }
+      },
+
+      disabled: {
+        type: Boolean,
+        observer: '_onDisableChange',

[Dan Beam, 2017/02/23 20:49:14]

nit: changed

+      },
     },
 
     /**
      * Selects the given value.
      */
      select: function(value) {
       var newItem = this._valueToItem(value);
       if (newItem && newItem.hasAttribute('disabled')) {
         return;
       }
@@ skipping 39 matching lines @@
     },
 
     _onLeftKey: function(event) {
       Polymer.IronMenubarBehaviorImpl._onLeftKey.apply(this, arguments);
       this._activateFocusedItem();
     },
 
     _onRightKey: function(event) {
       Polymer.IronMenubarBehaviorImpl._onRightKey.apply(this, arguments);
       this._activateFocusedItem();
-    }
-  });
+    },
+
+    _onDisableChange: function(disabled) {
+      if (disabled)
+        this.removeAttribute('tabindex');
+      else
+        this.tabindex = 0;
+    },
+  });