[MD History] Factor out a common HistoryListBehavior.

chrome/browser/resources/md_history/list_container.js

Index: chrome/browser/resources/md_history/list_container.js
diff --git a/chrome/browser/resources/md_history/list_container.js b/chrome/browser/resources/md_history/list_container.js
index 93d430d098c6298aea140073b56f7115f9d31d2b..6e5aab71365fa2fe069e6636ba19aadd890756cf 100644
--- a/chrome/browser/resources/md_history/list_container.js
+++ b/chrome/browser/resources/md_history/list_container.js
@@ -85,8 +85,7 @@ Polymer({
   },
 
   unselectAllItems: function(count) {
-    /** @type {HistoryListElement} */ (this.$['infinite-list'])
-        .unselectAllItems(count);
+    this.getSelectedList_().unselectAllItems(count);
   },
 
   /**
@@ -114,7 +113,6 @@ Polymer({
   /** @private */
   loadMoreHistory_: function() { this.queryHistory(true); },
 
-
   /**
    * @param {HistoryQuery} info
    * @param {!Array<HistoryEntry>} results
@@ -140,7 +138,7 @@ Polymer({
 
   /** @private */
   onDialogConfirmTap_: function() {
-    this.$['infinite-list'].deleteSelected();
+    this.$.content.selectedItem.deleteSelected();

[tsergeant, 2016/08/09 23:20:00]

Nit: Change this one as well.

[calamity, 2016/08/10 04:25:38]

Done.

     this.$.dialog.close();
   },
 
@@ -176,13 +174,21 @@ Polymer({
     menu.closeMenu();
   },
 
+  /**
+   * @return {HTMLElement}
+   * @private
+   */
+  getSelectedList_: function() {

[tsergeant, 2016/08/09 23:20:00]

Ultra nit: Move this up or down so that it's not between the two menu item
handlers (since they're a pretty logical grouping).

[calamity, 2016/08/10 04:25:38]

Done.

+    return this.$.content.selectedItem;
+  },
+
   /** @private */
   onRemoveFromHistoryTap_: function() {
     var menu = /** @type {CrSharedMenuElement} */(this.$.sharedMenu);
     md_history.BrowserService.getInstance()
         .deleteItems([menu.itemData])
         .then(function(items) {
-          this.$['infinite-list'].removeDeletedHistory_(items);
+          this.$.content.selectedItem.removeItemsByPath(items[0].path);

[tsergeant, 2016/08/09 23:20:00]

Nit: And this one

[calamity, 2016/08/10 04:25:38]

Done.

           // This unselect-all is to reset the toolbar when deleting a selected
           // item. TODO(tsergeant): Make this automatic based on observing list
           // modifications.