[MD Bookmarks] Scroll selected folder into view in sidebar.

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 94cc5e7a665fea47fdf550a04549d56e42d91e4c..c02e8155b5334b3e4ba4e85ff22ed26748bec3cc 100644
--- a/chrome/browser/resources/md_bookmarks/folder_node.js
+++ b/chrome/browser/resources/md_bookmarks/folder_node.js
@@ -61,6 +61,12 @@ Polymer({
     });
 
     this.updateFromStore();
+
+    if (this.isSelectedFolder_) {
+      this.async(function() {
+        this.scrollIntoViewIfNeeded();
+      });
+    }
   },
 
   /** @return {HTMLElement} */