add prototype of alt-input for stopwatch in toolbox, phetsims/a11y-re…

…search#166

js/StopwatchNode.js

@@ -15,6 +15,7 @@ import InstanceRegistry from '../../phet-core/js/documentation/InstanceRegistry.
 import merge from '../../phet-core/js/merge.js';
 import StringUtils from '../../phetcommon/js/util/StringUtils.js';
 import DragListener from '../../scenery/js/listeners/DragListener.js';
+import KeyboardDragListener from '../../scenery/js/listeners/KeyboardDragListener.js';
 import Circle from '../../scenery/js/nodes/Circle.js';
 import HBox from '../../scenery/js/nodes/HBox.js';
 import Node from '../../scenery/js/nodes/Node.js';
@@ -80,6 +81,10 @@ class StopwatchNode extends Node {
       // options propagated to the DragListener.
       dragListenerOptions: {
         start: _.noop
+      },
+      keyboardDragListenerOptions: {
+        start: _.noop
+
       }
     }, options );
     assert && assert( !options.hasOwnProperty( 'maxValue' ), 'options.maxValue no longer supported' );
@@ -135,7 +140,10 @@ class StopwatchNode extends Node {
 
     const backgroundNode = new ShadedRectangle( new Bounds2( 0, 0,
       contents.width + 2 * options.xMargin, contents.height + 2 * options.yMargin ), {
-      baseColor: options.backgroundBaseColor
+      baseColor: options.backgroundBaseColor,
+      // pdom
+      tagName: 'div',
+      focusable: true
     } );
     contents.center = backgroundNode.center;
 
@@ -144,6 +152,8 @@ class StopwatchNode extends Node {
 
     super( options );
 
+    this.backgroundNode = backgroundNode;
+
     // Disable the reset button when time is zero, and enable the play/pause button when not at the max time
     const timeListener = time => {
       resetButton.enabled = time > 0;
@@ -209,11 +219,25 @@ class StopwatchNode extends Node {
         optionsStart();
       };
 
+      const keyboardDragListenerOptions = merge( {
+        positionProperty: stopwatch.positionProperty,
+        dragBoundsProperty: adjustedDragBoundsProperty
+      }, options.keyboardDragListenerOptions );
+
+      // Add moveToFront to any start function that the client provided.
+      const keyboardOptionsStart = keyboardDragListenerOptions.start;
+      keyboardDragListenerOptions.start = () => {
+        this.moveToFront();
+        keyboardOptionsStart();
+      };
+
       // Dragging, added to background so that other UI components get input events on touch devices.
       // If added to 'this', touchSnag will lock out listeners for other UI components.
       this.dragListener = new DragListener( dragListenerOptions );
       backgroundNode.addInputListener( this.dragListener );
 
+      backgroundNode.addInputListener( new KeyboardDragListener( keyboardDragListenerOptions ) );
+
       // Move to front on pointer down, anywhere on this Node, including interactive subcomponents.
       this.addInputListener( {
         down: () => this.moveToFront()
@@ -249,6 +273,15 @@ class StopwatchNode extends Node {
     assert && phet.chipper.queryParameters.binder && InstanceRegistry.registerDataURL( 'scenery-phet', 'StopwatchNode', this );
   }
 
+  /**
+   * Forward to the background
+   * @override
+   * @public
+   */
+  focus() {
+    this.backgroundNode.focus();
+  }
+
   /**
    * @param {function(number):string} numberFormatter
    * @public