MD Settings: Display: Fix overscan dialog for <dialog>

chrome/browser/resources/settings/device_page/display_overscan_dialog.html

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/classes/iron-flex-layout.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="/icons.html">
 <link rel="import" href="/settings_shared_css.html">
 
 <dom-module id="settings-display-overscan-dialog">
@@ skipping 15 matching lines @@
        font-size: 150%;
      }
      #move > div.shift {
        background: black;
        color: white;
        font-size: 100%;
        margin: 0 8px;
        padding: 4px 8px 0;
      }
     </style>
-    <dialog is="cr-dialog" id="dialog" class="layout vertical" on-close="close">
+    <dialog is="cr-dialog" id="dialog" on-close="close">
       <div class="title">$i18n{displayOverscanPageTitle}</div>
       <div class="body">
         <div class="label self-start" >$i18n{displayOverscanInstructions}</div>
         <div class="details layout horizontal around-justified self-stretch">
           <div class="layout vertical center">
             <div class="layout horizontal">
               <iron-icon icon="cr:expand-less"></iron-icon>
             </div>
             <div class="layout horizontal">
               <iron-icon icon="settings:chevron-left"></iron-icon>
@@ skipping 19 matching lines @@
           $i18n{displayOverscanReset}
         </paper-button>
         <paper-button class="primary-button"  on-tap="onSaveTap_">
           $i18n{displayOverscanSave}
         </paper-button>
       </div>
     </dialog>
   </template>
   <script src="display_overscan_dialog.js"></script>
 </dom-module>