MD History: Delete button in the toolbar allows deletion of multiple history-items.

chrome/browser/resources/md_history/history_card.html

 <link rel="import" href="chrome://resources/polymer/v1_0/polymer/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/shadow.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout.html">
 <link rel="import" href="chrome://history/history_item.html">
 
 <dom-module id="history-card">
   <template>
     <style>
       :host {
         @apply(--layout-center);
@@ skipping 36 matching lines @@
     <div id="main-container">
       <div id="date-accessed">[[historyDate]]</div>
       <div id="history-item-list">
         <template is="dom-repeat" items="{{historyItems}}"
             as="historyItem">
           <history-item time-accessed="{{historyItem.dateTimeOfDay}}"
               website-title="{{historyItem.title}}"
               website-domain="{{historyItem.domain}}"
               website-url="{{historyItem.url}}"
               starred="{{historyItem.starred}}"
-              selected="{{historyItem.selected}}"
-              timestamp="{{historyItem.time}}">

[calamity, 2016/01/21 00:11:08]

Why did this disappear?

[hsampson, 2016/01/21 05:34:46]

Because it wasn't isn't being used yet, and later on the data associated with
the drop-down menu will be the array of timestamps rather than just one
timestamp.

+              selected="{{historyItem.selected}}">
           </history-item>
-          <template is="dom-if" if="{{needsTimeGap_(index, historyItem)}}">
+          <template is="dom-if"
+              if="{{needsTimeGap_(index, historyItems.length)}}">
             <div id="time-gap-separator"></div>
           </template>
         </template>
       </div>
     </div>
   </template>
   <script src="chrome://history/history_card.js"></script>
 </dom-module>