MD Settings: add a bunch of dialog (X) aria-labels

chrome/browser/resources/settings/bluetooth_page/bluetooth_device_dialog.html

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_scrollable_behavior.html">
 <link rel="import" href="chrome://resources/html/cr.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-list/iron-list.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input.html">
 <link rel="import" href="../bluetooth_page/bluetooth_device_list_item.html">
 <link rel="import" href="../settings_shared_css.html">
@@ skipping 51 matching lines @@
 
       /* .confirm indicates a confirmation passkey. */
       span.confirm {
         color: #999;
         font-size: 153.85%;  /* 20px / 13px */
         font-weight: 600;  /* semibold */
         margin: 0 20px;
       }
     </style>
     <dialog is="cr-dialog" id="dialog" on-cancel="onDialogCanceled_"
-        on-closed="onDialogCanceled_">
+        close-text="$i18n{close}" on-closed="onDialogCanceled_">
       <div class="title">$i18n{bluetoothPairDevicePageTitle}</div>
       <div class="body">
         <div class="contents layout vertical center center-justified">
           <template is="dom-if" if="[[isDialogType_(dialogId, 'pairDevice')]]">
             <div id="pairing" class="settings-box first layout vertical center
                 center-justified">
               <div class="dialog-message">
                 [[getMessage_(pairingDevice, pairingEvent_)]]
               </div>
               <div hidden$="[[!showEnterPincode_(pairingEvent_)]]">
@@ skipping 48 matching lines @@
         </template>
         <template is="dom-if" if="[[isDialogType_('connectError', dialogId)]]">
           <paper-button  on-tap="close">$i18n{bluetoothDismiss}
           </paper-button>
         </template>
       </div>
     </dialog>
   </template>
   <script src="bluetooth_device_dialog.js"></script>
 </dom-module>