Implement quantum ink splashes

sky/framework/sky-menu-item.sky

 <!--
 // Copyright 2015 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.
 -->
 <import src="sky-element.sky" />
 <import src="sky-icon.sky" />
 
 <sky-element attributes="icon:string">
 <template>
@@ skipping 21 matching lines @@
 </template>
 <script>
 import "dart:sky";
 
 @Tagname('sky-menu-item')
 class SkyMenuItem extends SkyElement {
   SkyIcon _icon;
   Element _label;
 
   void shadowRootReady() {
+    super.shadowRootReady();

[eseidel, 2015/02/24 23:39:12]

This will still work, correct?

+
     _icon = shadowRoot.querySelector('sky-icon');
     _icon.type = "${icon}_grey600";
   }
 
   void iconChanged(String oldValue, String newValue) {
     if (_icon != null)
       _icon.type = "${newValue}_grey600";
   }
 }
 
 _init(script) => register(script, SkyMenuItem);
 </script>
 </sky-element>