Band selection: Add handling for layout changes.

Previously, the app would crash druing band selection after the layout had changed.

Change-Id: I51ed2908d30e16f4d77769c798dfcef5f1ee1602
diff --git a/src/com/android/documentsui/DirectoryFragment.java b/src/com/android/documentsui/DirectoryFragment.java
index e15e6e0..462ffd2 100644
--- a/src/com/android/documentsui/DirectoryFragment.java
+++ b/src/com/android/documentsui/DirectoryFragment.java
@@ -573,6 +573,9 @@
         }
 
         mRecView.setLayoutManager(layout);
+        // TODO: Once b/23691541 is resolved, use a listener within MultiSelectManager instead of
+        // imperatively calling this function.
+        mSelectionManager.handleLayoutChanged();
         // setting layout manager automatically invalidates existing ViewHolders.
         mThumbSize = new Point(thumbSize, thumbSize);
     }