Adds initial support for flutter create of apps and plugins. This is derived from the current FDE example app and sample plugin, adding template values where relevant.
Since the APIs/tooling/template aren't stable yet, the app template includes a version marker, which will be updated each time there's a breaking change. The build now checks that the template version matches the version known by that version of the tool, and gives a specific error message when there's a mismatch, which improves over the current breaking change experience of hitting whatever build failure the breaking change causes and having to figure out that the problem is that the runner is out of date. It also adds a warning to the create output about the fact that it won't be stable.
Plugins don't currently have a version marker since in practice this is not a significant problem for plugins yet the way it is for runners; we can add it later if that changes.
Fixes#30704
* Fix web test flakiness; enable web golden tests
The fix is three-part:
- Only allow one test to load _and_ test at any point in time.
- Use a fresh Chrome instance for each test file.
- Increase Cirrus resources.
The first two changes only fix the "Unknown error loading" error, but not hanging tests. The resource increase also prevents hanging tests.
Other minor changes:
- Remove test batching (it's no longer necessary)
- Fix the Chrome class, which was using the wrong Completer.
Fixes#51010
The test package differentiates between passing and not passing this
argument. A previous version had a bug that treated passing `0`
identically to not passing the argument, and the flutter test runner
relied on this bug by always passing a value and using a default of `0`.
- Remove the argument defaults throughout to make it clear that `null`
is a valid value and the default.
- Remove the argument defaulting on the argument parser.
- Update the wording of the usage for this argument, this will also be
updated on the `package:test` side.
* Remove usages of StackTraceMapper
This class will be replaced with a function type in `test_api`, clean up
usages ahead of time.
In `build_script.dart` the only reference to `StackTraceMapper` is in
the `browser_test.dart` file, but since nothing would call
`setStackTraceMapper` from that import it should be safe to remove the
definition. After reading a serialized mapper from the
`test.browser.mapper` channel, it was ignored.
In `flutter_web_platform.dart` we only were reading from `_mappers`,
never putting values in, so we can remove it entirely. The `load()`
function was never called with a `mapper` argument.
