fix sky element

sky/framework/sky-element/sky-element.sky

Index: sky/framework/sky-element/sky-element.sky
diff --git a/sky/framework/sky-element/sky-element.sky b/sky/framework/sky-element/sky-element.sky
index c064255a71039288b1587cab39f90f385b50b54a..c401028deeadee509ca5ba931a9b47f8b836ce97 100644
--- a/sky/framework/sky-element/sky-element.sky
+++ b/sky/framework/sky-element/sky-element.sky
@@ -5,7 +5,9 @@
 -->
 <link rel="import" href="TemplateBinding.sky" />
 <script>
-var Base = Object.create(HTMLElement.prototype, {
+var Base = {
+  __proto__: HTMLElement.prototype,
+
   register: function() {
     // |this| is prototype
     var template = document.currentScript.previousElementSibling;
@@ -41,7 +43,7 @@ var Base = Object.create(HTMLElement.prototype, {
 
   attributeChanged: function(attrName, oldValue, newValue) {
     // override
-  },
+  }
 };
 
 function SkyElement(prototype) {