[MD settings] remove unused underscore class

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

 <link rel="import" href="chrome://resources/cr_elements/icons.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-icon/iron-icon.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-icon-button/paper-icon-button.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/paper-submenu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu-button/paper-menu-button.html">
 <link rel="import" href="/i18n_setup.html">
@@ skipping 27 matching lines @@
         on-paper-submenu-open="onToggle_" on-paper-submenu-close="onToggle_">
       <div class="menu-trigger settings-box" hidden$="[[allSites]]" actionable>
         <div class="flex" id="header">
           [[computeSiteListHeader_(sites, categoryEnabled)]]
         </div>
         <iron-icon id="icon" icon="cr:expand-more"></iron-icon>
       </div>
 
       <div class="list-frame menu-content vertical-list" id="listContainer">
         <template is="dom-repeat" items="[[sites]]">
-          <div class="list-item underscore">
+          <div class="list-item">
             <div class="favicon-image"
                 style$="[[computeSiteIcon(item.originForDisplay)]]"
                 on-tap="onOriginTap_" actionable></div>
             <div class="middle" on-tap="onOriginTap_" actionable>
               <div>[[item.originForDisplay]]</div>
               <div class="secondary">[[item.embeddingOriginForDisplay]]</div>
             </div>
             <paper-menu-button hidden$="[[allSites]]">
               <paper-icon-button icon="cr:more-vert"
                   class="dropdown-trigger">
@@ skipping 31 matching lines @@
                 class="primary-button no-upper">
               $i18n{addSiteLink}
             </paper-button>
           </div>
         </template>
       </div>
     </paper-submenu>
   </template>
   <script src="site_list.js"></script>
 </dom-module>