Merge "Fix potential NPE when saving fragment state."

core/java/android/app/FragmentManager.java

@@ -1538,6 +1538,9 @@ final class FragmentManagerImpl extends FragmentManager {
                     FragmentManagerImpl.VIEW_STATE_TAG, f.mSavedViewState);
         }
         if (!f.mUserVisibleHint) {
+            if (result == null) {
+                result = new Bundle();
+            }
             // Only add this if it's not the default value
             result.putBoolean(FragmentManagerImpl.USER_VISIBLE_HINT_TAG, f.mUserVisibleHint);
         }