[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..74d199479b02871bcc426c33f522fe4566fff04d 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.$['infinite-list'])
-        .unselectAllItems(count);
+    this.$.content.selectedItem.unselectAllItems(count);

[tsergeant, 2016/08/05 01:39:09]

Nit: Maybe extract this.$.content.selectedItem into a getter which returns a
HistoryListBehavior.

The idea being that then we are forced by closure in this file to not know which
type of list we are dealing with.

[calamity, 2016/08/09 02:56:00]

So this is exactly why I was asking how behaviors worked with Closure yesterday.
I can't seem to get a Type for HistoryListBehavior =(

[tsergeant, 2016/08/09 04:37:54]

That's unfortunate. I think it would be worthwhile to write a getter if you can
anyway, though.

[calamity, 2016/08/09 05:28:30]

Done.

   },
 
   /**
@@ -140,7 +139,7 @@ Polymer({
 
   /** @private */
   onDialogConfirmTap_: function() {
-    this.$['infinite-list'].deleteSelected();
+    this.$.content.selectedItem.deleteSelected();
     this.$.dialog.close();
   },
 
@@ -182,7 +181,7 @@ Polymer({
     md_history.BrowserService.getInstance()
         .deleteItems([menu.itemData])
         .then(function(items) {
-          this.$['infinite-list'].removeDeletedHistory_(items);
+          this.$.content.selectedItem.removeItemsByPath(items[0].path);
           // This unselect-all is to reset the toolbar when deleting a selected
           // item. TODO(tsergeant): Make this automatic based on observing list
           // modifications.