MD User Manager: fixes accessibility issues

chrome/browser/resources/md_user_manager/create_profile.html

 <link rel="import" href="chrome://md-user-manager/import_supervised_user.html">
 <link rel="import" href="chrome://md-user-manager/profile_browser_proxy.html">
 <link rel="import" href="chrome://md-user-manager/shared_styles.html">
 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/util.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
@@ skipping 64 matching lines @@
         flex-wrap: wrap;
         margin: -12px;
       }
 
       #icons paper-button {
         background: var(--paper-grey-300);
         border: 1px solid rgba(0, 0, 0, .12);
         margin: 12px;
         min-width: 0;
         padding: 6px 4px;
+        --paper-button-flat-keyboard-focus: {
+          outline: auto;
+        };
       }
 
       #icons paper-button[active] {
         border-color: var(--google-blue-500);
       }
 
-      #icons paper-button:focus:not([active]) {
-        outline: 1px dotted #666;
-      }
-
       paper-checkbox {
         --paper-checkbox-label-spacing: 16px;
         --paper-checkbox-size: 20px;
         --primary-text-color: var(--main-text-color);
         margin-top: 24px;
       }
 
       #supervised-user-container {
         -webkit-padding-start: 36px;
       }
@@ skipping 111 matching lines @@
         <paper-button id="save" class="action primary" on-tap="onSaveTap_"
             disabled="[[isSaveDisabled_(createInProgress_, profileName_)]]">
           $i18n{createProfileConfirm}
         </paper-button>
       </div>
       <import-supervised-user id="importUserPopup"></import-supervised-user>
     </div>
   </template>
   <script src="chrome://md-user-manager/create_profile.js"></script>
 </dom-module>