cr-elements fixes for Polymer 0.8

ui/webui/resources/cr_elements/v0_8/demo_element.html

 <link rel="import" href="chrome://resources/polymer/v0_8/polymer/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/v0_8/cr_button/cr_button.html">
 <link rel="import" href="chrome://resources/cr_elements/v0_8/cr_checkbox/cr_checkbox.html">
 <link rel="import" href="chrome://resources/cr_elements/v0_8/cr_collapse/cr_collapse.html">
 <link rel="import" href="chrome://resources/cr_elements/v0_8/cr_input/cr_input.html">
 <link rel="import" href="chrome://resources/cr_elements/v0_8/cr_network_icon/cr_network_icon.html">
 <link rel="import" href="chrome://resources/cr_elements/v0_8/cr_toggle_button/cr_toggle_button.html">
 
 <dom-module id="cr-demo-element">
   <template>
@@ skipping 21 matching lines @@
       <h3>cr-input</h3>
       <cr-input label="Input" value="{{inputValue}}"></cr-input>
       <span>Input.value=</span><span>{{inputValue}}</span>
     </div>
     <div>
       <h3>cr-network-icon</h3>
       <cr-network-icon></cr-network-icon>
     </div>
     <div>
       <h3>cr-toggle-button</h3>
-      <div horizontal layout>

[michaelpg, 2015/05/18 21:06:48]

these attributes don't do anything now, and normal inline flow actually looks
better than using class="horizontal layout".

+      <div>
+        <cr-toggle-button checked="{{toggleButtonChecked}}"></cr-toggle-button>
         <span>Toggle Button</span>
-        <cr-toggle-button></cr-toggle-button>
+      </div>
+      <div>
+        <span>Bound Checkbox</span>
+        <cr-checkbox checked="{{toggleButtonChecked}}"></cr-checkbox>
       </div>
     </div>
   </template>
   <script src="demo_element.js"></script>
 </dom-module>