Create a common directory of widgets and css.

appengine/chromium_rietveld/new_static/common/cr-keyboard.html

 <!-- Copyright (c) 2014 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file. -->
 
 <!--
     Use to add keyboard shortcuts to your components. The last inserted component
     will always receive the events (and others will not). This prevents the
     common bug where you have two listeners and multiple actions are taken for
     the same keyboard shortcut.
 
@@ skipping 119 matching lines @@
                 return instance.isActive() && instance.hasAttribute("on-key-" + key);
             });
             if (instance && instance.fire("key-" + key, event).defaultPrevented)
                 event.preventDefault();
         }
 
         window.addEventListener("keydown", handleKeyDown);
     })();
     </script>
 </polymer-element>