MD Settings: Touch up cr-dialog footers

ui/webui/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/assert.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/default-theme.html">
 
 <dom-module id="cr-dialog">
   <template>
     <style>
       :host {
         border: 0;
         border-radius: 2px;
         bottom: 0;
         box-shadow: 0px 0px 16px rgba(0, 0, 0, 0.12),
                     0px 16px 16px rgba(0, 0, 0, 0.24);
         color: inherit;
         padding: 0;
         top: 0;
         width: 512px;
       }
 
       :host::backdrop {
         background-color: rgba(0, 0, 0, 0.6);
         bottom: 0;
         left: 0;
         position: fixed;
         right: 0;
         top: 0;
       }
 
       .title-container {
         align-items: center;
-        /* TODO(dbeam): should this be a --settings-separator-line? */
-        border-bottom: 1px solid rgba(0, 0, 0, 0.14);
+        border-bottom: 1px solid var(--divider-color);
         display: flex;
         min-height: 52px;
       }
 
       :host ::content .title {
         font-size: 123.07%; /* (16px / 13px) * 100 */
       }
 
       #close {
         --paper-icon-button: {
@@ skipping 33 matching lines @@
         margin-bottom: 12px;
         margin-top: 12px;
       }
 
       :host ::content .button-container .cancel-button {
         -webkit-margin-end: 8px;
         color: var(--paper-grey-600);
       }
 
       :host ::content .footer {
-        background-color: var(--paper-grey-200);
         border-bottom-left-radius: inherit;
         border-bottom-right-radius: inherit;
         margin: 0;
         padding: 12px 20px;
       }
+
+      :host ::content .border-top-divider {
+        border-top: 1px solid var(--divider-color);
+      }
     </style>
     <div class="title-container">
       <content select=".title"></content>
       <paper-icon-button icon="cr:clear" on-tap="cancel" id="close"
           aria-label$="[[closeText]]">
       </paper-icon-button>
     </div>
     <div class="body-container">
       <content select=".body"></content>
     </div>
     <content select=".button-container"></content>
     <content select=".footer"></content>
   </template>
   <script src="cr_dialog.js"></script>
 </dom-module>