Remove wstrings from bookmarks, part 9.

app/tree_node_model.h

Index: app/tree_node_model.h
diff --git a/app/tree_node_model.h b/app/tree_node_model.h
index 4a1458bf4a27c3e32c23d22ffca0ae163e5c5efa..b294911fb84fe754cbb8a291fa2abbddba5c9104 100644
--- a/app/tree_node_model.h
+++ b/app/tree_node_model.h
@@ -273,9 +273,9 @@ class TreeNodeModel : public TreeModel {
 
   // Sets the title of the specified node.
   virtual void SetTitle(TreeModelNode* node,
-                        const std::wstring& title) {
+                        const string16& title) {
     DCHECK(node);
-    AsNode(node)->SetTitle(WideToUTF16Hack(title));
+    AsNode(node)->SetTitle(title);
     NotifyObserverTreeNodeChanged(node);
   }