Add scaffolds for performance tests of DocumentsUI

Bug: 27370274
Change-Id: I14dea1b85cd84c8bb3c0eee27b2954108bfa4f8b
diff --git a/src/com/android/documentsui/DirectoryLoader.java b/src/com/android/documentsui/DirectoryLoader.java
index 13b7b14..d2e918c 100644
--- a/src/com/android/documentsui/DirectoryLoader.java
+++ b/src/com/android/documentsui/DirectoryLoader.java
@@ -59,7 +59,6 @@
     private CancellationSignal mSignal;
     private DirectoryResult mResult;
 
-
     public DirectoryLoader(Context context, int type, RootInfo root, DocumentInfo doc, Uri uri,
             int userSortOrder, boolean inSearchMode) {
         super(context, ProviderExecutor.forAuthority(root.authority));
@@ -84,6 +83,7 @@
         final String authority = mUri.getAuthority();
 
         final DirectoryResult result = new DirectoryResult();
+        result.doc = mDoc;
 
         // Use default document when searching
         if (mSearchMode) {