acc66a77fe
In the Flutter engine, we plan to expand and start using Dart actions to
rely more on the GN build system, and less on home-grown (Python/Bash)
tooling. To that end, we'll start generating dart_snapshot and dart_test
rules that are invokved the same way locally (via `et`) and on CI, with
a goal of making all of our tests programatically discoverable.
We need the `metadata` field (a standard GN field) in order to tag our
outputs (i.e. `metadata = { action_type = ['dart_executable'] }`);
see https://gn.googlesource.com/gn/+/main/docs/reference.md#var_metadata.
Bug: https://github.com/flutter/flutter/issues/147013
Change-Id: I0e44209b8aade13cec99b944583a90a7c13d3300
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/386582
Reviewed-by: Zach Anderson <zra@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>