Extract GetNodeByID() method from BookmarkModel.

chrome/browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc

Index: chrome/browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc
diff --git a/chrome/browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc b/chrome/browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc
index 0a3be770b211ff976e9cd78122854752bc3bf518..698a04458287bf31c92bd8506a651b62067044e5 100644
--- a/chrome/browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc
+++ b/chrome/browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc
@@ -68,12 +68,12 @@ namespace {
 
 // Returns a single bookmark node from the argument ID.
 // This returns NULL in case of failure.
-const BookmarkNode* GetNodeFromString(
-    BookmarkModel* model, const std::string& id_string) {
+const BookmarkNode* GetNodeFromString(BookmarkModel* model,
+                                      const std::string& id_string) {
   int64 id;
   if (!base::StringToInt64(id_string, &id))
     return NULL;
-  return model->GetNodeByID(id);
+  return bookmark_utils::GetNodeByID(model, id);
 }
 
 // Gets a vector of bookmark nodes from the argument list of IDs.