[MD History] Implement grouped history UI.

chrome/browser/resources/md_history/history_item.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-item',
+cr.define('md_history', function() {
+  var HistoryItem = Polymer({
+    is: 'history-item',
 
-  properties: {
-    // Underlying HistoryEntry data for this item. Contains read-only fields
-    // from the history backend, as well as fields computed by history-list.
-    item: {
-      type: Object,
-      observer: 'showIcon_'
+    properties: {
+      // Underlying HistoryEntry data for this item. Contains read-only fields
+      // from the history backend, as well as fields computed by history-list.
+      item: {type: Object, observer: 'showIcon_'},
+
+      // True if the website is a bookmarked page.
+      starred: {type: Boolean, reflectToAttribute: true},
+
+      // Search term used to obtain this history-item.
+      searchTerm: {type: String},
+
+      selected: {type: Boolean, notify: true},
+
+      isCardStart: {type: Boolean, reflectToAttribute: true},
+
+      isCardEnd: {type: Boolean, reflectToAttribute: true},
+
+      hasTimeGap: {type: Boolean},
+
+      numberOfItems: {type: Number}
     },
 
-    // True if the website is a bookmarked page.
-    starred: {
-      type: Boolean,
-      reflectToAttribute: true
+    observers: ['setSearchedTextToBold_(item.title, searchTerm)'],
+
+    /**
+     * When a history-item is selected the toolbar is notified and increases
+     * or decreases its count of selected items accordingly.
+     * @private
+     */
+    onCheckboxSelected_: function() {
+      this.fire('history-checkbox-select', {
+        countAddition: this.$.checkbox.checked ? 1 : -1
+      });
     },
 
-    // Search term used to obtain this history-item.
-    searchTerm: {
-      type: String
+    /**
+     * Fires a custom event when the menu button is clicked. Sends the details
+     * of the history item and where the menu should appear.
+     */
+    onMenuButtonTap_: function(e) {
+      this.fire('toggle-menu', {
+        target: Polymer.dom(e).localTarget,
+        item: this.item,
+      });
+
+      // Stops the 'tap' event from closing the menu when it opens.
+      e.stopPropagation();
     },
 
-    selected: {
-      type: Boolean,
-      notify: true
+    /**
+     * Set the favicon image, based on the URL of the history item.
+     * @private
+     */
+    showIcon_: function() {
+      this.$.icon.style.backgroundImage =
+          cr.icon.getFaviconImageSet(this.item.url);
     },
 
-    isCardStart: {
-      type: Boolean,
-      reflectToAttribute: true
+    /**
+     * Updates the page title. If the result was from a search, highlights any
+     * occurrences of the search term in bold.
+     * @private
+     */
+    setSearchedTextToBold_: function() {
+      var i = 0;
+      var titleElem = this.$.title;
+      var titleText = this.item.title;
+
+      if (this.searchTerm == '' || this.searchTerm == null) {
+        titleElem.textContent = titleText;
+        return;
+      }
+
+      var re = new RegExp(quoteString(this.searchTerm), 'gim');
+      var match;
+      titleElem.textContent = '';
+      while (match = re.exec(titleText)) {
+        if (match.index > i)
+          titleElem.appendChild(document.createTextNode(
+              titleText.slice(i, match.index)));
+        i = re.lastIndex;
+        // Mark the highlighted text in bold.
+        var b = document.createElement('b');
+        b.textContent = titleText.substring(match.index, i);
+        titleElem.appendChild(b);
+      }
+      if (i < titleText.length)
+        titleElem.appendChild(
+            document.createTextNode(titleText.slice(i)));
     },
 
-    isCardEnd: {
-      type: Boolean,
-      reflectToAttribute: true
+    selectionNotAllowed_: function() {
+      return !loadTimeData.getBoolean('allowDeletingHistory');
     },
 
-    hasTimeGap: {
-      type: Boolean
-    },
+    /**
+     * Generates the title for this history card.
+     * @param {number} numberOfItems The number of items in the card.
+     * @param {string} search The search term associated with these results.
+     * @private
+     */
+    cardTitle_: function(numberOfItems, historyDate, search) {
+      if (!search)
+        return this.item.dateRelativeDay;
 
-    numberOfItems: {
-      type: Number
+      var resultId = numberOfItems == 1 ? 'searchResult' : 'searchResults';
+      return loadTimeData.getStringF('foundSearchResults', numberOfItems,
+          loadTimeData.getString(resultId), search);
     }
-  },
-
-  observers: [
-    'setSearchedTextToBold_(item.title, searchTerm)'
-  ],
+  });
 
   /**
-   * When a history-item is selected the toolbar is notified and increases
-   * or decreases its count of selected items accordingly.
+   * Check whether the time difference between the given history item and the
+   * next one is large enough for a spacer to be required.
+   * @param {Array<HistoryEntry>} visits
+   * @param {number} currentIndex
+   * @param {string} searchedTerm
+   * @return {boolean} Whether or not time gap separator is required.
    * @private
    */
-  onCheckboxSelected_: function() {
-    this.fire('history-checkbox-select', {
-      countAddition: this.$.checkbox.checked ? 1 : -1
-    });
-  },
+  HistoryItem.needsTimeGap = function(visits, currentIndex, searchedTerm) {
+    if (currentIndex >= visits.length - 1 || visits.length == 0)
+      return false;
 
-  /**
-   * Fires a custom event when the menu button is clicked. Sends the details of
-   * the history item and where the menu should appear.
-   */
-  onMenuButtonTap_: function(e) {
-    this.fire('toggle-menu', {
-      target: Polymer.dom(e).localTarget,
-      item: this.item,
-    });
+    var currentItem = visits[currentIndex];
+    var nextItem = visits[currentIndex + 1];
 
-    // Stops the 'tap' event from closing the menu when it opens.
-    e.stopPropagation();
-  },
+    if (searchedTerm)
+      return currentItem.dateShort != nextItem.dateShort;
 
-  /**
-   * Set the favicon image, based on the URL of the history item.
-   * @private
-   */
-  showIcon_: function() {
-    this.$.icon.style.backgroundImage =
-        cr.icon.getFaviconImageSet(this.item.url);
-  },
+    return currentItem.time - nextItem.time > BROWSING_GAP_TIME &&
+        currentItem.dateRelativeDay == nextItem.dateRelativeDay;
+  };
 
-  /**
-   * Updates the page title. If the result was from a search, highlights any
-   * occurrences of the search term in bold.
-   * @private
-   */
-  setSearchedTextToBold_: function() {
-    var i = 0;
-    var titleElem = this.$.title;
-    var titleText = this.item.title;
-
-    if (this.searchTerm == '' || this.searchTerm == null) {
-      titleElem.textContent = titleText;
-      return;
-    }
-
-    var re = new RegExp(quoteString(this.searchTerm), 'gim');
-    var match;
-    titleElem.textContent = '';
-    while (match = re.exec(titleText)) {
-      if (match.index > i)
-        titleElem.appendChild(document.createTextNode(
-            titleText.slice(i, match.index)));
-      i = re.lastIndex;
-      // Mark the highlighted text in bold.
-      var b = document.createElement('b');
-      b.textContent = titleText.substring(match.index, i);
-      titleElem.appendChild(b);
-    }
-    if (i < titleText.length)
-      titleElem.appendChild(
-          document.createTextNode(titleText.slice(i)));
-  },
-
-  selectionNotAllowed_: function() {
-    return !loadTimeData.getBoolean('allowDeletingHistory');
-  },
-
-  /**
-   * Generates the title for this history card.
-   * @param {number} numberOfItems The number of items in the card.
-   * @param {string} search The search term associated with these results.
-   * @private
-   */
-  cardTitle_: function(numberOfItems, historyDate, search) {
-    if (!search)
-      return this.item.dateRelativeDay;
-
-    var resultId = numberOfItems == 1 ? 'searchResult' : 'searchResults';
-    return loadTimeData.getStringF('foundSearchResults', numberOfItems,
-        loadTimeData.getString(resultId), search);
-  }
+  return { HistoryItem: HistoryItem };
 });