all ui components should have enabledProperty and visibleProperty phe…

…tioFeatured, phetsims/phet-io#1517

js/NumberPicker.js

@@ -124,7 +124,6 @@ define( function( require ) {
 
       // a11y
       pageKeyboardStep: 2 // {number} - change in value when using page up/page down, see AccessibleNumberSpinner
-
     }, options );
 
     // {Color|string|Property.<Color|string} color of arrows and top/bottom gradient when pressed
@@ -141,6 +140,8 @@ define( function( require ) {
     assert && assert( options.disabledOpacity > 0 && options.disabledOpacity < 1,
       `invalid disabledOpacity: ${options.disabledOpacity}` );
 
+    PhetioObject.mergePhetioComponentOptions( { visibleProperty: { phetioFeatured: true } }, options );
+
     var self = this;
     Node.call( this );
 
@@ -167,6 +168,9 @@ define( function( require ) {
         phetioFeatured: true
       }, options.enabledPropertyOptions ) );
     }
+    else {
+      assert && assert( this.enabledProperty.phetioFeatured, 'provided enabledProperty must be phetioFeatured' );
+    }
 
     //------------------------------------------------------------
     // Nodes