user Polymer builtin layout attributes

bower.json

@@ -2,7 +2,6 @@
   "name": "core-field",
   "private": true,
   "dependencies": {
-    "core-icon": "Polymer/core-icon#master",
-    "core-layout": "Polymer/core-layout#master"
+    "polymer": "Polymer/polymer#master"
   }
 }

core-field.html

@@ -7,7 +7,7 @@
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 -->
 
-<link rel="import" href="../core-layout/core-layout.html">
+<link rel="import" href="../polymer/polymer.html">
 
 <!--
 The `core-field` supplies a horizontal layout, anticipating an input.
@@ -17,20 +17,18 @@
     <core-field>
       <core-icon icon="menu" size="48"></core-icon>
       <label>I'm a label!</label>
-      <input placeholder="I have a label" core-flex>
+      <input placeholder="I have a label" flex>
     </core-field>
 
 @group Polymer Core Elements
 @element core-field
 @homepage github.io
 -->
-<polymer-element name="core-field" noscript>
+<polymer-element name="core-field" noscript center horizontal layout>
 <template>
 
   <link rel="stylesheet" href="core-field.css">
 
-  <core-layout align="center"></core-layout>
-
   <content select="*"></content>
 
 </template>

demo.html

@@ -35,23 +35,23 @@
 
   <core-field>
     <div class="icon"></div>
-    <input placeholder="hi!" core-flex>
+    <input placeholder="hi!" flex>
   </core-field>
 
   <core-field>
     <div class="icon"></div>
-    <input placeholder="Search" core-flex>
+    <input placeholder="Search" flex>
     <icon></icon>
   </core-field>
 
   <core-field>
     <div class="icon"></div>
     <label>I'm a label!</label>
-    <input placeholder="I have a label" core-flex>
+    <input placeholder="I have a label" flex>
   </core-field>
 
   <core-field>
-    <input placeholder="I have no icon" core-flex>
+    <input placeholder="I have no icon" flex>
   </core-field>
 
 </body>