Guard against monkey crash.

Bug: 27784445
Change-Id: I4ba6e02e0cdb6857661a824ae0888feac6762a05
diff --git a/src/com/android/settings/dashboard/DashboardSummary.java b/src/com/android/settings/dashboard/DashboardSummary.java
index 448a77d..c111992 100644
--- a/src/com/android/settings/dashboard/DashboardSummary.java
+++ b/src/com/android/settings/dashboard/DashboardSummary.java
@@ -139,6 +139,7 @@
     @Override
     public void onSaveInstanceState(Bundle outState) {
         super.onSaveInstanceState(outState);
+        if (mLayoutManager == null) return;
         outState.putInt(EXTRA_SCROLL_POSITION, mLayoutManager.findFirstVisibleItemPosition());
     }