500a8c0a72
Fixes https://github.com/dart-lang/linter/issues/3023 This fix is a little unusually large because I have to add some elements to both the mock flutter package, and the mock SDK. This affects some completion tests. Cq-Include-Trybots: luci.dart.try:flutter-analyze-try,analyzer-win-release-try,pkg-win-release-try Change-Id: I44b68754f756cfe1cf99518957d74c4af56043f1 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/368260 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Commit-Queue: Samuel Rawlins <srawlins@google.com>