MD History: Simplify flex layout in <history-list>

chrome/browser/resources/md_history/history_list.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 Polymer({
   is: 'history-list',
 
   properties: {
     // The search term for the current query. Set when the query returns.
     searchedTerm: {
@@ skipping 226 matching lines @@
    * @return {boolean}
    * @private
    */
   isCardEnd_: function(item, i, length) {
     if (length == 0 || i > length - 1)
       return false;
     return i == length - 1 ||
         this.historyData_[i].dateRelativeDay !=
         this.historyData_[i + 1].dateRelativeDay;
   },
+
+  /**
+   * @param {number} index
+   * @return {boolean}
+   * @private
+   */
+  isFirstItem_: function(index) {
+    return index == 0;
+  }
 });