Fix an analyzer error in http and barback.

pkg/barback/lib/src/utils.dart

Index: pkg/barback/lib/src/utils.dart
diff --git a/pkg/barback/lib/src/utils.dart b/pkg/barback/lib/src/utils.dart
index ad97460c54facd74633c1d944eb7fc8c35002f98..71576ff32c8abf5586ef3ca53a5e7c7e6f52a2c8 100644
--- a/pkg/barback/lib/src/utils.dart
+++ b/pkg/barback/lib/src/utils.dart
@@ -85,7 +85,10 @@ String byteToHex(int byte) {
 /// If [input] is a [TypedData], this just returns a view on [input].
 Uint8List toUint8List(List<int> input) {
   if (input is Uint8List) return input;
-  if (input is TypedData) return new Uint8List.view(input.buffer);
+  if (input is TypedData) {
+    // TODO(nweiz): remove "as" when issue 11080 is fixed.
+    return new Uint8List.view((input as TypedData).buffer);
+  }
   return new Uint8List.fromList(input);
 }