Don't try using a detached fragment.

Test: builds, boots
Bug: 36486843
Change-Id: I3e2d2bcd56edcc86370f4b64dabdf155d63f40d3
diff --git a/src/com/android/settings/users/EditUserPhotoController.java b/src/com/android/settings/users/EditUserPhotoController.java
index 03b959a..c348b4aa 100644
--- a/src/com/android/settings/users/EditUserPhotoController.java
+++ b/src/com/android/settings/users/EditUserPhotoController.java
@@ -240,6 +240,7 @@
 
             @Override
             protected void onPostExecute(Void result) {
+                if (!mFragment.isAdded()) return;
                 cropPhoto();
             }
         }.execute();