Address same issue as PR 57. Android browser is not supported, but im…

…plemented fix since it's trivial.

src/CustomElements.js

@@ -172,26 +172,26 @@ if (useNative) {
     // prototype for precise mixing in
     if (!Object.__proto__) {
       // default prototype
-      var native = HTMLElement.prototype;
+      var nativePrototype = HTMLElement.prototype;
       // work out prototype when using type-extension
       if (definition.is) {
         var inst = document.createElement(definition.tag);
-        native = Object.getPrototypeOf(inst);
+        nativePrototype = Object.getPrototypeOf(inst);
       }
       // ensure __proto__ reference is installed at each point on the prototype
       // chain.
       // NOTE: On platforms without __proto__, a mixin strategy is used instead
       // of prototype swizzling. In this case, this generated __proto__ provides
       // limited support for prototype traversal.
       var proto = definition.prototype, ancestor;
-      while (proto && (proto !== native)) {
+      while (proto && (proto !== nativePrototype)) {
         var ancestor = Object.getPrototypeOf(proto);
         proto.__proto__ = ancestor;
         proto = ancestor;
       }
     }
     // cache this in case of mixin
-    definition.native = native;
+    definition.native = nativePrototype;
   }
 
   // SECTION 4