This implements dual compile via the newly available flutter.js bootstrapping APIs for intelligent build fallback.
* Users can now use the `FlutterLoader.load` API from flutter.js
* Flutter tool injects build info into the `index.html` of the user so that the bootstrapper knows which build variants are available to bootstrap
* The semantics of the `--wasm` flag for `flutter build web` have changed:
- Instead of producing a separate `build/web_wasm` directory, the output goes to the `build/web` directory like a normal web build
- Produces a dual build that contains two build variants: dart2wasm+skwasm and dart2js+CanvasKit. The dart2wasm+skwasm will only work on Chrome in a cross-origin isolated context, all other environments will fall back to dart2js+CanvasKit.
- `--wasm` and `--web-renderer` are now mutually exclusive. Since there are multiple build variants with `--wasm`, the web renderer cannot be expressed via a single command-line flag. For now, we are hard coding what build variants are produced with the `--wasm` flag, but I plan on making this more customizable in the future.
* Build targets now can optionally provide a "build key" which can uniquely identify any specific parameterization of that build target. This way, the build target can invalidate itself by changing its build key. This works a bit better than just stuffing everything into the environment defines because (a) it doesn't invalidate the entire build, just the targets which are affected and (b) settings for multiple build variants don't translate well to the flat map of environment defines.
Relates to tracker issue:
- https://github.com/flutter/flutter/issues/128251
This PR includes 3 major updates:
- Adding the `commandHasTerminal` parameter for `Event.flutterCommandResult`
- In `packages/flutter_tools/lib/src/runner/flutter_command.dart`
- Adding the new event for `sendException` from package:usage to be `Event.exception` (this event can be used by all dash tools)
- In `packages/flutter_tools/lib/runner.dart`
- Migrating the generic `UsageEvent` which was only used for Apple related workflows for iOS and macOS. I did an initial analysis in this [sheet](https://docs.google.com/spreadsheets/d/11KJLkHXFpECMX7tw-trNkYSr5MHDG15XNGv6TgLjfQs/edit?resourcekey=0-j4qdvsOEEg3wQW79YlY1-g#gid=0) to identify all the call sites
- Found in several files, highlighted in the sheet above
Our current top crasher is an unclear error when ProcessManager fails to resolve an executable path. To fix this, we'd like to being adjusting the process resolution logic and adding more instrumentation to track failures. In order to begin the process, the ProcessManager has been folded back into the flutter tool
* [flutter_tools] handle case where file is deleted by other program
* Add test cases
* Update file_system.dart
* Update file_system_test.dart
* fix import
* make a static on ErrorHandligFS
* add support for no exit on failure
* address comments
* update doc comment to file or directory
Introduce BuildSystem.buildIncremental, which keeps an in-memory cache of timestamps instead of file hashes. This will be used to implement localization generation through the same build system API.
