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

chrome/browser/resources/settings/internet_page/network_proxy.html

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_network_behavior.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_network_indicator.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/md_select_css.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys/iron-a11y-keys.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-container.html">
@@ skipping 184 matching lines @@
       <paper-button id="saveManualProxy"
           on-tap="onSaveProxyTap_" class="action-button"
           disabled="[[!isSaveManualProxyEnabled_(networkProperties,
               proxyModified_, proxy_.*)]]">
         $i18n{save}
       </paper-button>
     </div>
 
     <!-- Confirm Allow shared proxies dialog -->
     <dialog is="cr-dialog" id="confirmAllowSharedDialog"
-        on-cancel="onAllowSharedDialogCancel_">
+        close-text="$i18n{close}" on-cancel="onAllowSharedDialogCancel_">
       <div class="title">$i18n{networkProxyAllowSharedWarningTitle}</div>
       <div class="body">$i18n{networkProxyAllowSharedWarningMessage}</div>
       <div class="button-container">
         <paper-button class="cancel-button"
             on-tap="onAllowSharedDialogCancel_">
           $i18n{cancel}
         </paper-button>
         <paper-button class="action-button"
             on-tap="onAllowSharedDialogConfirm_">
           $i18n{confirm}
         </paper-button>
       </div>
     </dialog>
   </template>
   <script src="network_proxy.js"></script>
 </dom-module>