WebUI: Polymer config tweaks for better performance.

chrome/browser/resources/md_history/history_item.html

 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/cr/ui/focus_row.html">
 <link rel="import" href="chrome://resources/html/polymer.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-styles/shadow.html">
 <link rel="import" href="chrome://resources/html/icon.html">
 <link rel="import" href="chrome://resources/html/util.html">
 <link rel="import" href="chrome://history/browser_service.html">
 <link rel="import" href="chrome://history/constants.html">
 <link rel="import" href="chrome://history/searched_label.html">
@@ skipping 213 matching lines @@
         <div id="title-and-domain">
           <a href="[[item.url]]" id="title" class="website-title"
               title="[[item.title]]" on-click="onLinkClick_"
               on-contextmenu="onLinkRightClick_">
             <history-searched-label title="[[item.title]]"
                 search-term="[[searchTerm]]"></history-searched-label>
           </a>
           <span id="domain">[[item.domain]]</span>
         </div>
         <div id="star-container">
-          <template is="dom-if" if="[[item.starred]]">
+          <template is="dom-if" if="[[item.starred]]" notify-dom-change>
             <button is="paper-icon-button-light" id="bookmark-star"
                 title="$i18n{removeBookmark}" on-click="onRemoveBookmarkTap_">
               <iron-icon icon="cr:star"></iron-icon>
             </button>
           </template>
         </div>
         <button is="paper-icon-button-light" id="menu-button"
             class="more-vert-button" title="$i18n{moreActionsButton}"
             on-click="onMenuButtonTap_">
           <div></div>
           <div></div>
           <div></div>
         </button>
       </div>
       <div id="time-gap-separator" hidden="[[!hasTimeGap]]"></div>
     </div>
   </template>
   <script src="chrome://history/history_item.js"></script>
 </dom-module>