[MD Bookmarks] Add Select for Bookmarks.

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 d58b28c2246418c6019b3f6fa11fc1e3b907eca4..7057ebf56e29fe11f6cc20417df8c9bbda2d0ddd 100644
--- a/chrome/browser/resources/md_bookmarks/folder_node.js
+++ b/chrome/browser/resources/md_bookmarks/folder_node.js
@@ -9,7 +9,7 @@ Polymer({
     /** @type {BookmarkTreeNode} */
     item: Object,
 
-    isSelected: {
+    isSelectedFolder: {
       type: Boolean,
       value: false,
       reflectToAttribute: true,
@@ -21,7 +21,7 @@ Polymer({
    * @return {string}
    */
   getFolderIcon_: function() {
-    return this.isSelected ? 'bookmarks:folder-open' : 'cr:folder';
+    return this.isSelectedFolder ? 'bookmarks:folder-open' : 'cr:folder';
   },
 
   /**
@@ -60,4 +60,12 @@ Polymer({
     }
     return false;
   },
+
+  /**
+   * @private
+   * @return {array<BookmarkTreeNode>}
+   */
+  getFolders_: function() {
+    return this.item.children.filter(i => !i.url);
+  },
 });