MD History: remove underline/bgcolor change on :hover

chrome/browser/resources/md_history/list_container.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_shared_menu/cr_shared_menu.html">
 <link rel="import" href="chrome://resources/cr_elements/shared_style_css.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-pages/iron-pages.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-item/paper-item.html">
 <link rel="import" href="chrome://history/grouped_list.html">
 <link rel="import" href="chrome://history/history_list.html">
 
 <dom-module id="history-list-container">
@@ skipping 13 matching lines @@
       #dialog .body {
         white-space: pre-wrap;
       }
 
       paper-item {
         -webkit-user-select: none;
         cursor: pointer;
         font: inherit;
         white-space: nowrap;
       }
-
-      paper-item:hover {
-        background: #eaeaea;
-      }
     </style>
     <iron-pages id="content" attr-for-selected="id"
         selected="[[selectedPage_]]">
       <history-list id="infinite-list" querying="[[queryState.querying]]"
           searched-term="[[queryResult.info.term]]"></history-list>
       <template is="dom-if" if="[[grouped]]">
         <history-grouped-list id="grouped-list"
             range="[[queryState.range]]"
             query-start-time="[[queryResult.info.queryStartTime]]"
             query-end-time="[[queryResult.info.queryEndTime]]"
@@ skipping 20 matching lines @@
       <paper-item id="menuMoreButton" on-tap="onMoreFromSiteTap_">
         $i18n{moreFromSite}
       </paper-item>
       <paper-item id="menuRemoveButton" on-tap="onRemoveFromHistoryTap_">
         $i18n{removeFromHistory}
       </paper-item>
     </cr-shared-menu>
   </template>
   <script src="chrome://history/list_container.js"></script>
 </dom-module>