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

chrome/browser/resources/md_history/history_card_manager.js

Index: chrome/browser/resources/md_history/history_card_manager.js
diff --git a/chrome/browser/resources/md_history/history_card_manager.js b/chrome/browser/resources/md_history/history_card_manager.js
index 6844515fc8ce23f55f008b3a95b2e296ce5c8484..dac054984329373beccaa422c97b4f0c6c3ae956 100644
--- a/chrome/browser/resources/md_history/history_card_manager.js
+++ b/chrome/browser/resources/md_history/history_card_manager.js
@@ -104,6 +104,7 @@ Polymer({
   /**
    * Cycle through each entry in historyDataByDay_ and set all items to be
    * unselected.
+   * @param {number} overallItemCount The number of items selected.
    */
   unselectAllItems: function(overallItemCount) {
     var historyCardData = this.historyDataByDay_;
@@ -116,13 +117,57 @@ Polymer({
               '.selected', false);
           overallItemCount--;
           if (overallItemCount == 0)
-            break;
+            return;
         }
       }
     }
   },
 
   /**
+   * Remove all selected items from the overall array so that they are also
+   * removed from view. Make sure that the card length and positioning is
+   * updated accordingly.
+   * @param {number} overallItemCount The number of items selected.
+   */
+  removeDeletedHistory: function(overallItemCount) {
+    for (var i = 0; i < this.historyDataByDay_.length; i++) {
+      var items = this.historyDataByDay_[i].historyItems;
+      var itemDeletedFromCard = false;
+
+      for (var j = items.length - 1; j >= 0; j--) {
+        if (items[j].selected) {

[calamity, 2016/02/02 05:34:58]

nit: Invert and use continue.

[hsampson, 2016/02/02 22:59:53]

Done.

+          this.splice('historyDataByDay_.' + i + '.historyItems', j, 1);
+          itemDeletedFromCard = true;
+          overallItemCount--;
+          if (overallItemCount == 0) {
+            this.removeEmptyCards_();
+            // If the last card has been removed don't try to update its size.
+            if (this.historyDataByDay_.length > i)

[calamity, 2016/02/02 05:34:58]

nit: Flip this around. Seeing a greater than comparison is making my head spin.

[hsampson, 2016/02/02 22:59:53]

Done.

+              this.$['infinite-list'].updateSizeForItem(i);
+            return;
+          }
+        }
+      }
+      if (itemDeletedFromCard)
+        this.$['infinite-list'].updateSizeForItem(i);
+    }
+  },
+
+  /**
+   * If a given day has had all the history it contains removed, remove this

[tsergeant, 2016/02/02 03:36:51]

Nit: Reword this comment.

The word 'given' implies that there's a parameter for removing a specific day.

(Although maybe don't worry too much, since history-card is due to be killed
anyway)

[hsampson, 2016/02/02 22:59:53]

Done.

+   * day from the array.
+   * @private
+   */
+  removeEmptyCards_: function() {
+    var historyCards = this.historyDataByDay_;
+    for (var i = historyCards.length - 1; i >= 0; i--) {
+      if (historyCards[i].historyItems.length == 0) {
+        this.splice('historyDataByDay_', i, 1);
+      }
+    }
+  },
+
+  /**
    * Adds the given items into historyDataByDay_. Adds items to the last
    * existing day if the date matches, creates a new element otherwise.
    * @param {string} date The date of the history items.
@@ -144,6 +189,34 @@ Polymer({
   },
 
   /**
+   * Based on which items are selected, collect an array of the info required
+   * for chrome.send('removeHistory', ...).
+   * @param {number} count The number of items that are selected.
+   * @return {Array<HistoryEntry>} toBeRemoved An array of objects which contain
+   * information on which history-items should be deleted.
+   */
+  getItemsToDelete: function(count) {

[calamity, 2016/02/02 05:34:58]

nit: getSelectedItems?

[hsampson, 2016/02/02 22:59:53]

Done.

+    var toBeRemoved = [];
+    for (var i = 0; i < this.historyDataByDay_.length; i++) {
+      var items = this.historyDataByDay_[i].historyItems;
+      for (var j = 0; j < items.length; j++) {
+        if (items[j].selected) {
+
+          toBeRemoved.push({
+            url: items[j].url,
+            timestamps: items[j].allTimestamps
+          });
+
+          count--;
+          if (count == 0)
+            return toBeRemoved;
+        }
+      }
+    }
+    return toBeRemoved;
+  },
+
+  /**
    * Called when the card manager is scrolled.
    * @private
    */