[null-safety] fix the snippets (#69122)

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Jonah Williams 2020-10-27 11:04:16 -07:00 committed by GitHub
parent 8c3d564ded
commit e9b18c1d9c
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@ -186,6 +186,7 @@ class SampleChecker {
/// Computes the headers needed for each sample file.
List<Line> get headers {
return _headers ??= <String>[
'// @dart = 2.9',
'// generated code',
"import 'dart:async';",
"import 'dart:convert';",