[MD Bookmarks] Remove the bookmarks-sidebar element.

chrome/browser/resources/md_bookmarks/folder_node.js

Index: chrome/browser/resources/md_bookmarks/folder_node.js
diff --git a/chrome/browser/resources/md_bookmarks/folder_node.js b/chrome/browser/resources/md_bookmarks/folder_node.js
index 2800bf00f1799e4faa9737c7eb5e0599db20114e..cdca80866605f6c672c20a96a3b318ed0449ee5d 100644
--- a/chrome/browser/resources/md_bookmarks/folder_node.js
+++ b/chrome/browser/resources/md_bookmarks/folder_node.js
@@ -64,6 +64,11 @@ Polymer({
     return this.$.container;
   },
 
+  /** @return {boolean} */
+  isPositiveDepth_: function() {
+    return this.depth >= 0;
+  },
+
   /**
    * @private
    * @return {string}