[MD History] Refactor history.html into a history-app element.

chrome/browser/resources/md_history/side_bar.js

Index: chrome/browser/resources/md_history/side_bar.js
diff --git a/chrome/browser/resources/md_history/side_bar.js b/chrome/browser/resources/md_history/side_bar.js
index 02108615aad6627772660df4b186abb659946ee9..11da2e42884c0a1912b197769c89dd3733c4949b 100644
--- a/chrome/browser/resources/md_history/side_bar.js
+++ b/chrome/browser/resources/md_history/side_bar.js
@@ -5,6 +5,13 @@
 Polymer({
   is: 'history-side-bar',
 
+  properties: {
+    selectedPage: {
+      type: String,
+      notify: true
+    }
+  },
+
   /**
    * Handles menu selection changes.
    * @param {Event} e
@@ -12,6 +19,6 @@ Polymer({
    */
   onSelect_: function(e) {
     this.fire('unselect-all');
-    this.fire('switch-display', {display: e.detail.item.id});
+    this.selectedPage = e.detail.item.getAttribute('view-id');
   },
 });