Fix NPE at startup

    Bug: 5676863

Change-Id: I673699e577f0ed2cfa85260f905ccccc0d852399
diff --git a/src/com/android/browser/Controller.java b/src/com/android/browser/Controller.java
index 52183eb..8dc05f8 100644
--- a/src/com/android/browser/Controller.java
+++ b/src/com/android/browser/Controller.java
@@ -1425,7 +1425,7 @@
             return;
         }
         MenuItem dest = menu.findItem(R.id.stop_reload_menu_id);
-        MenuItem src = tab.inPageLoad() ?
+        MenuItem src = ((tab != null) && tab.inPageLoad()) ?
                 menu.findItem(R.id.stop_menu_id):
                 menu.findItem(R.id.reload_menu_id);
         if (src != null) {