From a13f7be81bba0d6829b7a052146420a28e1eb6a9 Mon Sep 17 00:00:00 2001
From: Natalie Weizenbaum <nweiz@google.com>
Date: Thu, 19 Nov 2020 17:44:36 -0800
Subject: [PATCH] Apply the change in #1139 to the asynchronous source file
 (#1150)

---
 lib/src/async_import_cache.dart | 1 +
 lib/src/import_cache.dart       | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/src/async_import_cache.dart b/lib/src/async_import_cache.dart
index 8725200a0..1eb044c2f 100644
--- a/lib/src/async_import_cache.dart
+++ b/lib/src/async_import_cache.dart
@@ -160,6 +160,7 @@ Relative canonical URLs are deprecated and will eventually be disallowed.
     if (tuple == null) return null;
     var stylesheet =
         await importCanonical(tuple.item1, tuple.item2, tuple.item3);
+    if (stylesheet == null) return null;
     return Tuple2(tuple.item1, stylesheet);
   }
 
diff --git a/lib/src/import_cache.dart b/lib/src/import_cache.dart
index 110fb5c5c..1ac8ad7d5 100644
--- a/lib/src/import_cache.dart
+++ b/lib/src/import_cache.dart
@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_import_cache.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: 5293a11e290c86829547ddd982ee3b1b1536dc73
+// Checksum: ac91c195e290010a7e104f832a00a5ebb41a127a
 //
 // ignore_for_file: unused_import