From c6ae330320bf289ddc5dd73398a3e91ba9284830 Mon Sep 17 00:00:00 2001
From: Andrew Wilson <anwilson@chromium.org>
Date: Wed, 26 Aug 2015 14:14:44 -0700
Subject: [PATCH] Fix npe.

---
 packages/flutter/lib/widgets/mimic.dart | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/flutter/lib/widgets/mimic.dart b/packages/flutter/lib/widgets/mimic.dart
index eb6aa22cf8..df92c5e211 100644
--- a/packages/flutter/lib/widgets/mimic.dart
+++ b/packages/flutter/lib/widgets/mimic.dart
@@ -98,7 +98,9 @@ class Mimic extends GlobalKeyWatcher {
   void _setMimicable(widget) {
     if (_mimicable != widget) {
       _stopMimic();
-      widget.startMimic();
+      if (widget != null) {
+        widget.startMimic();
+      }
     }
     setState(() {
       _mimicable = widget;