WebUI: For cr-dialog, make Enter click the action-button, if it exists.

chrome/browser/resources/settings/people_page/people_page.html

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_expand_button/cr_expand_button.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/icon.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-collapse/iron-collapse.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
@@ skipping 357 matching lines @@
             page-title="$i18n{editPerson}">
           <settings-manage-profile profile-icon-url="[[profileIconUrl_]]"
               profile-name="[[profileName_]]" sync-status="[[syncStatus]]">
           </settings-manage-profile>
         </settings-subpage>
       </template>
 </if>
     </settings-animated-pages>
 
     <template is="dom-if" if="[[showDisconnectDialog_]]" restamp>
-      <dialog is="cr-dialog" id="disconnectDialog" ignore-popstate
+      <dialog is="cr-dialog" id="disconnectDialog"
+          ignore-popstate ignore-enter-key
           on-close="onDisconnectClosed_" close-text="$i18n{close}">
         <div class="title">$i18n{syncDisconnectTitle}</div>
         <div class="body">
           <div inner-h-t-m-l="[[
               getDisconnectExplanationHtml_(syncStatus.domain)]]">
           </div>
         </div>
         <div class="button-container">
           <paper-button on-tap="onDisconnectCancel_" class="cancel-button">
             $i18n{cancel}
@@ skipping 40 matching lines @@
 <if expr="chromeos">
     <template is="dom-if" if="[[showEasyUnlockTurnOffDialog_]]">
       <easy-unlock-turn-off-dialog id="easyUnlockTurnOffDialog"
           on-close="onEasyUnlockTurnOffDialogClose_">
       </easy-unlock-turn-off-dialog>
     </template>
 </if>
   </template>
   <script src="people_page.js"></script>
 </dom-module>