Safari actually pauses execution of our unit tests if the window becomes occluded or non-visible. As such, I am inserting this egregious hack which just makes the Safari window frontmost every 2 seconds so that the unit tests don't get stalled out.
This should fix https://github.com/flutter/flutter/issues/150023
This PR makes some major revisions to our flutter.js bootstrapper.
* Modularize flutter.js into multiple files to make it a little simpler to manage from source code. They are still bundled into a single .js file by esbuild.
* Added a `types.d.ts` file which contains declarations of the types of some of the objects used in the flutter.js API
* Deprecated the old `FlutterLoader.loadEntrypoint` API and added a new function simply called `FlutterLoader.load`, which has a few more capabilities:
- A build tool can inject a build config, that may describe multiple builds that `FlutterLoader.load` can attempt to use. It will use the first one that is compatible with the browser environment and the user's configuration.
- It can also load wasm flutter apps.
- It also pre-loads and instantiates CanvasKit (and Skwasm) as necessary depending on the build configuration.
- `FlutterLoader.load` also immediately takes a flutter configuration object. If an `onEntrypointLoaded` callback is not provided by the user, it just does the expected thing and initializes the engine and immediately starts the app, passing the configuration along as needed.
* `flutter.js` has the engine hash built into it now, which allows it to ascertain the correct CDN URLs for both CanvasKit and Skwasm.
This switches over to using Chrome for Testing instead of Chromium. This requires some changes from the recipes repo (https://flutter-review.googlesource.com/c/recipes/+/51482) in order to coordinate the change in filestructure on the mac versions.
We recently upgraded a bot in the try pool to macOS 13 and I noticed a couple of tests have leaked through to it and we're not ready for tests to run on macOS 13 yet.
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
