update elements and fix some bugs

test/iron_a11y_keys_behavior_test.dart

 @TestOn('browser')
 library polymer_elements.test.iron_a11y_keys_behavior_test;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
 import 'dart:js';
 import 'package:polymer_elements/iron_a11y_keys_behavior.dart';
 import 'package:polymer_interop/polymer_interop.dart';
 import 'package:polymer/polymer.dart';
@@ skipping 39 matching lines @@
         keys.removeOwnKeyBindings();
   
         pressEnter(keys);
         expect(keys.keyCount, 0);
 
         // **Dart Note**: All our key bindings are imperative, so this part of
         // the test isn't valid.
         // pressSpace(keys);
         // expect(keys.keyCount, 1);
       });
+
+      test('allows propagation beyond the key combo handler', () {
+        var called = false;
+        var done = document.on['keydown'].first.then((_) {
+          called = true;
+        });
+
+        pressEnter(keys);
+
+        expect(called, true);
+
+        return done;
+      });
   
       group('edge cases', () {
         test('knows that `spacebar` is the same as `space`', () {
           var event = new CustomEvent('keydown');
           new JsObject.fromBrowserObject(event)['key'] = 'spacebar';
           expect(keys.keyboardEventMatchesKeys(event, 'space'), true);
         });
       });
   
       group('matching keyboard events to keys', () {
@@ skipping 64 matching lines @@
         keys = fixture('BehaviorKeys');
       });
   
       test('bindings in other behaviors are transitive', () {
         pressEnter(keys);
         pressSpace(keys);
   
         expect(keys.keyCount, 2);
       });
     });
+
+    group('stopping propagation automatically', () {
+      setUp(() {
+        keys = fixture('NonPropagatingKeys');
+      });
+
+      test('does not propagate key events beyond the combo handler', () async {
+        var called = false;
+
+        document.on['keydown'].first.then((_) {
+          called = true;
+        });
+
+        pressEnter(keys);
+        await wait(1);
+
+        expect(called, isFalse);
+      });
+    });
   });
 }
 
 @behavior
 abstract class KeysTestBehavior implements PolymerMixin, PolymerBase, HtmlElement, IronA11yKeysBehavior {
   @property
   int keyCount = 0;
 
   @property
   Event lastEvent;
@@ skipping 41 matching lines @@
 
 @PolymerRegister('x-a11y-behavior-keys')
 class XA11yBehaviorKeys extends PolymerElement
     with IronA11yKeysBehavior, KeysTestBehavior, XA11yBehavior {
   XA11yBehaviorKeys.created() : super.created();
 
   ready() {
     addOwnKeyBinding('space', 'keyHandler');
   }
 }