[MD settings] remove unused underscore class

chrome/browser/resources/settings/site_settings/protocol_handlers.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.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-item/paper-item.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu/paper-menu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu-button/paper-menu-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="/i18n_setup.html">
 <link rel="import" href="/settings_shared_css.html">
@@ skipping 20 matching lines @@
       <paper-toggle-button id="toggle" checked="{{categoryEnabled}}"
           on-change="onToggleChange_"></paper-toggle-button>
     </div>
 
     <template is="dom-repeat" items="[[protocols]]" as="protocol">
       <div class="protocol">[[protocol.protocol]]</div>
 
       <div class="list-frame menu-content vertical-list">
         <template is="dom-repeat" items="[[protocol.handlers]]">
 
-          <div class="list-item underscore">
+          <div class="list-item">
             <div class="middle" >
               <div>[[item.host]]</div>
               <div class="secondary"
                   hidden$="[[!isDefault_(index, protocol.default_handler)]]">
                 $i18n{handlerIsDefault}
               </div>
             </div>
 
             <paper-menu-button>
               <paper-icon-button icon="cr:more-vert"
@@ skipping 12 matching lines @@
               </paper-menu>
             </paper-menu-button>
           </div>
 
         </template>
       </div>
     </template>
   </template>
   <script src="protocol_handlers.js"></script>
 </dom-module>