Avoid NPE until we understand better.

Bug: 6450986
Change-Id: I68af8fedc419cd3142ba2bb7530b77aca7718123
diff --git a/src/com/android/settings/DataUsageSummary.java b/src/com/android/settings/DataUsageSummary.java
index 4882fbe..1bdc1d1 100644
--- a/src/com/android/settings/DataUsageSummary.java
+++ b/src/com/android/settings/DataUsageSummary.java
@@ -1067,6 +1067,10 @@
         public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
             final Context context = view.getContext();
             final AppItem app = (AppItem) parent.getItemAtPosition(position);
+
+            // TODO: sigh, remove this hack once we understand 6450986
+            if (mUidDetailProvider == null || app == null) return;
+
             final UidDetail detail = mUidDetailProvider.getUidDetail(app.appId, true);
             AppDetailsFragment.show(DataUsageSummary.this, app, detail.label);
         }