This pull request aims for improved readability, based on issue #146600.
```dart
// before
List<SupportedPlatform> getSupportedPlatforms({bool includeRoot = false}) {
final List<SupportedPlatform> platforms = includeRoot
? <SupportedPlatform>[SupportedPlatform.root]
: <SupportedPlatform>[];
if (android.existsSync()) {
platforms.add(SupportedPlatform.android);
}
if (ios.exists) {
platforms.add(SupportedPlatform.ios);
}
if (web.existsSync()) {
platforms.add(SupportedPlatform.web);
}
if (macos.existsSync()) {
platforms.add(SupportedPlatform.macos);
}
if (linux.existsSync()) {
platforms.add(SupportedPlatform.linux);
}
if (windows.existsSync()) {
platforms.add(SupportedPlatform.windows);
}
if (fuchsia.existsSync()) {
platforms.add(SupportedPlatform.fuchsia);
}
return platforms;
}
// after
List<SupportedPlatform> getSupportedPlatforms({bool includeRoot = false}) {
return <SupportedPlatform>[
if (includeRoot) SupportedPlatform.root,
if (android.existsSync()) SupportedPlatform.android,
if (ios.exists) SupportedPlatform.ios,
if (web.existsSync()) SupportedPlatform.web,
if (macos.existsSync()) SupportedPlatform.macos,
if (linux.existsSync()) SupportedPlatform.linux,
if (windows.existsSync()) SupportedPlatform.windows,
if (fuchsia.existsSync()) SupportedPlatform.fuchsia,
];
}
```
This adds support for adding the `--wasm` flag to `flutter run` and `flutter drive`
* Emits errors if you attempt to use the skwasm renderer without the `--wasm` flag
* Emits errors if you try to use `--wasm` when not using a web device
* Uses the skwasm renderer by default if you pass `--wasm` and no `--web-renderer`
* Adds support for `flutter test --wasm`.
* The test compilation flow is a bit different now, so that it supports compilers other than DDC. Specifically, when we run a set of unit tests, we generate a "switchboard" main function that imports each unit test and runs the main function for a specific one based off of a value set by the JS bootstrapping code. This way, there is one compile step and the same compile output is invoked for each unit test file.
* Also, removes all references to `dart:html` from flutter/flutter.
* Adds CI steps for running the framework unit tests with dart2wasm+skwasm
* These steps are marked as `bringup: true`, so we don't know what kind of failures they will result in. Any failures they have will not block the tree at all yet while we're still in `bringup: true`. Once this PR is merged, I plan on looking at any failures and either fixing them or disabling them so we can get these CI steps running on presubmit.
This fixes https://github.com/flutter/flutter/issues/126692
### Context:
DDC modules are abstractions over how libraries are loaded/updated. The entirety of google3 uses the DDC/legacy module system due to its flexibility extensibility over the other two (ES6 and AMD/RequireJS). Unifying DDC's module system saves us from duplicating work and will allow us to have finer grained control over how JS modules are loaded. This is a a prerequisite to features such as hot reload.
### Overview:
This change plumbs a boolean flag through flutter_tools that switches between DDC (new) and AMD (current) modules. This mode is automatically applied when `--extra-front-end-options=--dartdevc-module-format=ddc` is specified alongside `flutter run`. Other important additions include:
* Splitting Flutter artifacts between DDC and AMD modules
* Adding unit tests for the DDC module system
* Additional bootstrapper logic for the DDC module system
We don't expect to see any user-visible behavior or performance differences.
This is dependent on [incoming module system support in DWDS](https://github.com/dart-lang/webdev/pull/2295) and [additional artifacts in the engine](https://github.com/flutter/engine/pull/47783).
This is part of a greater effort to deprecate the AMD module system: https://github.com/dart-lang/sdk/issues/52361
This PR implements the functionality described above and hides it behind
the `--experimental-faster-testing` flag of `flutter test`.
### The following are some performance measurements from test runs
conducted on GitHub Actions
run 1 logs:
https://github.com/derekxu16/flutter_test_ci/actions/runs/8008029772/attempts/1
run 2 logs:
https://github.com/derekxu16/flutter_test_ci/actions/runs/8008029772/attempts/2
run 3 logs:
https://github.com/derekxu16/flutter_test_ci/actions/runs/8008029772/attempts/3
**length of `flutter test --reporter=expanded test/animation
test/foundation` step**
run 1: 54s
run 2: 52s
run 3: 56s
average: 54s
**length of `flutter test --experimental-faster-testing
--reporter=expanded test/animation test/foundation` step**
run 1: 27s
run 2: 27s
run 3: 29s
average: 27.67s (~48.77% shorter than 54s)
**length of `flutter test --reporter=expanded test/animation
test/foundation test/gestures test/painting test/physics test/rendering
test/scheduler test/semantics test/services` step**
run 1: 260s
run 2: 270s
run 3: 305s
average: 278.33s
**length of `flutter test --experimental-faster-testing
--reporter=expanded test/animation test/foundation test/gestures
test/painting test/physics test/rendering test/scheduler test/semantics
test/services` step**
from a clean build (right after deleting the build folder):
run 1: 215s
run 2: 227s
run 3: 245s
average: 229s (~17.72% shorter than 278.33s)
Note that in reality, `test/material` was not passed to `flutter test`
in the trials below. All of the test files under `test/material` except
for `test/material/icons_test.dart` were listed out individually
**length of `flutter test --reporter=expanded test/material` step**
run 1: 408s
run 2: 421s
run 3: 451s
average: 426.67s
**length of `flutter test --experimental-faster-testing
--reporter=expanded test/material` step**
run 1: 382s
run 2: 373s
run 3: 400s
average: 385s (~9.77% shorter than 426.67s)
---------
Co-authored-by: Dan Field <dnfield@google.com>
This is an attempt at a reland of https://github.com/flutter/flutter/pull/141396
The main changes here that are different than the original PR is fixes to wire up the `flutter test` command properly with the web renderer.
Dual Web Compile has had some issues where `flutter test` is not respecting the `--web-renderer` flag for some reason. I haven't gotten entirely to the bottom of the issue, but for now we need to rever these changes while I investigate. This reverts the following PRs:
https://github.com/flutter/flutter/pull/143128https://github.com/flutter/flutter/pull/141396
While doing this revert, I had a few merge conflicts with https://github.com/flutter/flutter/pull/142760, and I tried to resolve the merge conflicts within the spirit of that PR's change, but @chingjun I might need your input on whether the imports I have modified are okay with regards to the change you were making.
Reland of https://github.com/flutter/flutter/pull/142709.
The revert of the revert is in the first commit, the fix in the commit on top.
The move of the fakes for packages/flutter_tools/test/general.shard/resident_runner_test.dart was erroneous before, as it was trying to use setters instead of a private field. This PR changes the private `_devFS` field in the fake to be a public `fakeDevFS` in line with other fakes.
## Original PR description
Native assets in other build systems are not built with `package:native_assets_builder` invoking `build.dart` scripts. Instead all packages have their own blaze rules. Therefore we'd like to not depend on `package:native_assets_builder` from flutter tools in g3 at all.
This PR aims to move the imports of `native_assets_builder` and `native_assets_cli` into the `isolated/` directory and into the files with a `main` function that are not used in with other build systems.
In order to be able to remove all imports in files used by other build systems, two new interfaces are added `HotRunnerNativeAssetsBuilder` and `TestCompilerNativeAssetsBuilder`. New parameters are then piped all the way through from the entry points:
* bin/fuchsia_tester.dart
* lib/executable.dart
The build_system/targets dir is already excluded in other build systems.
So, after this PR only the two above files and build_system/targets import from `isolated/native_assets/` and only `isolated/native_assets/` import `package:native_assets_cli` and `package:native_assets_builder`.
Context:
* https://github.com/flutter/flutter/issues/142041
Reverts flutter/flutter#142709
Initiated by: vashworth
Reason for reverting: `Mac tool_tests_general` started failing on this commit: https://ci.chromium.org/ui/p/flutter/builders/prod/Mac%20tool_tests_general/15552/overview
Original PR Author: dcharkes
Reviewed By: {christopherfujino, chingjun, reidbaker}
This change reverts the following previous change:
Original Description:
Native assets in other build systems are not built with `package:native_assets_builder` invoking `build.dart` scripts. Instead all packages have their own blaze rules. Therefore we'd like to not depend on `package:native_assets_builder` from flutter tools in g3 at all.
This PR aims to move the imports of `native_assets_builder` and `native_assets_cli` into the `isolated/` directory and into the files with a `main` function that are not used in with other build systems.
In order to be able to remove all imports in files used by other build systems, two new interfaces are added `HotRunnerNativeAssetsBuilder` and `TestCompilerNativeAssetsBuilder`. New parameters are then piped all the way through from the entry points:
* bin/fuchsia_tester.dart
* lib/executable.dart
The build_system/targets dir is already excluded in other build systems.
So, after this PR only the two above files and build_system/targets import from `isolated/native_assets/` and only `isolated/native_assets/` import `package:native_assets_cli` and `package:native_assets_builder`.
Context:
* https://github.com/flutter/flutter/issues/142041
Native assets in other build systems are not built with `package:native_assets_builder` invoking `build.dart` scripts. Instead all packages have their own blaze rules. Therefore we'd like to not depend on `package:native_assets_builder` from flutter tools in g3 at all.
This PR aims to move the imports of `native_assets_builder` and `native_assets_cli` into the `isolated/` directory and into the files with a `main` function that are not used in with other build systems.
In order to be able to remove all imports in files used by other build systems, two new interfaces are added `HotRunnerNativeAssetsBuilder` and `TestCompilerNativeAssetsBuilder`. New parameters are then piped all the way through from the entry points:
* bin/fuchsia_tester.dart
* lib/executable.dart
The build_system/targets dir is already excluded in other build systems.
So, after this PR only the two above files and build_system/targets import from `isolated/native_assets/` and only `isolated/native_assets/` import `package:native_assets_cli` and `package:native_assets_builder`.
Context:
* https://github.com/flutter/flutter/issues/142041
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.
It's now possible to natively compile a flutter app for windows-arm64. Cross-compilation is not yet implemented.
Uses arm64 artifacts now available for Dart/Flutter. Platform detection is based on Abi class, provided by Dart. Depending if Dart is an arm64 or x64 binary, the Abi is set accordingly. Initial bootstrap of dart artifacts (update_dart_sdk.ps1) is checking PROCESSOR_ARCHITECTURE environment variable, which is the way to detect host architecture on Windows.
This is available only for master channel (on other channels, it fallbacks to windows-x64).
On windows-x64, it produces an x64 app. On windows-arm64, it produces an arm64 app.
Reverts flutter/flutter#137618
Initiated by: Jasguerrero
This change reverts the following previous change:
Original Description:
It's now possible to natively compile a flutter app for
windows-arm64. Cross-compilation is not yet implemented.
Uses arm64 artifacts now available for Dart/Flutter.
Platform detection is based on Abi class, provided by Dart. Depending if
Dart is an arm64 or x64 binary, the Abi is set accordingly.
Initial bootstrap of dart artifacts (update_dart_sdk.ps1) is checking
PROCESSOR_ARCHITECTURE environment variable, which is the way to detect
host architecture on Windows.
This is available only for master channel (on other channels, it
fallbacks to windows-x64).
On windows-x64, it produces an x64 app. On windows-arm64, it produces an
arm64 app.
It's now possible to natively compile a flutter app for
windows-arm64. Cross-compilation is not yet implemented.
Uses arm64 artifacts now available for Dart/Flutter.
Platform detection is based on Abi class, provided by Dart. Depending if
Dart is an arm64 or x64 binary, the Abi is set accordingly.
Initial bootstrap of dart artifacts (update_dart_sdk.ps1) is checking
PROCESSOR_ARCHITECTURE environment variable, which is the way to detect
host architecture on Windows.
This is available only for master channel (on other channels, it
fallbacks to windows-x64).
On windows-x64, it produces an x64 app. On windows-arm64, it produces an
arm64 app.
Relands #136851, which was rolled back in #137121
package:coverage has been rolled, so the breakages should be fixed.
Also, in this reland I've changed the `coverableLineCache` parameter to
be optional, which is safer.
Reverts flutter/flutter#136851
Initiated by: CaseyHillers
This change reverts the following previous change:
Original Description:
One of the reasons gathering coverage information is expensive is that we have to force compile every function in the libraries we're interested in. Without this, functions that haven't been invoked (so haven't been compiled) won't have any line number information, so the coverage tool doesn't know which lines to add to the list of misses. In flutter's case, the test infra spawns many VMs, and each of these needs to recompile all those libraries.
To fix this, we need a way of skipping force compilation for libraries we've already seen in previous tests, without losing the information about which lines in each library are coverable. So I [added](https://github.com/dart-lang/coverage/pull/466) the `coverableLineCache` to `coverage.collect` in package:coverage v1.7.0. This cache starts out empty, but fills up with lists of all the lines that are coverable for every library as coverage is gathered. package:coverage can then tell the VM not to force compile any libraries in this cache (using `getSourceReport`'s `librariesAlreadyCompiled` param). So the first test suite will still have to compile everything, but subsequent test suites will be much faster.
This speeds up coverage collection significantly, for large test suites:
| Running flutter/packages/flutter tests... | Time | Overhead |
| --- | --- | --- |
| without coverage | 8:53 | - |
| with coverage | 20:25 | 130% |
| with `coverableLineCache` | 12:21 | 40% |
Bug: https://github.com/flutter/flutter/issues/100751
One of the reasons gathering coverage information is expensive is that we have to force compile every function in the libraries we're interested in. Without this, functions that haven't been invoked (so haven't been compiled) won't have any line number information, so the coverage tool doesn't know which lines to add to the list of misses. In flutter's case, the test infra spawns many VMs, and each of these needs to recompile all those libraries.
To fix this, we need a way of skipping force compilation for libraries we've already seen in previous tests, without losing the information about which lines in each library are coverable. So I [added](https://github.com/dart-lang/coverage/pull/466) the `coverableLineCache` to `coverage.collect` in package:coverage v1.7.0. This cache starts out empty, but fills up with lists of all the lines that are coverable for every library as coverage is gathered. package:coverage can then tell the VM not to force compile any libraries in this cache (using `getSourceReport`'s `librariesAlreadyCompiled` param). So the first test suite will still have to compile everything, but subsequent test suites will be much faster.
This speeds up coverage collection significantly, for large test suites:
| Running flutter/packages/flutter tests... | Time | Overhead |
| --- | --- | --- |
| without coverage | 8:53 | - |
| with coverage | 20:25 | 130% |
| with `coverableLineCache` | 12:21 | 40% |
Bug: https://github.com/flutter/flutter/issues/100751
Reverts flutter/flutter#135249
Initiated by: zanderso
This change reverts the following previous change:
Original Description:
Changes golden tests on CanvasKit to use Layer.toImage instead of browser APIs for screenshots. This brings it more in line with other platforms and should also fix some async timing bugs with tests.
This implements https://github.com/flutter/flutter/issues/132654#issuecomment-1738221257, namely:
Make `Chromium.close` more robust:
* Send `SIGTERM` and wait up to 5 seconds, if the process exited, great! Return from the function.
* If the process has not exited, then send a `SIGKILL`, which is a much firmer way to exit a process. Same as before, wait up to 5 seconds, if the process exited, great! Return from the function.
* If it still hasn't exited then give up trying to exit Chromium, just print a warning to the console and return from the function.
Bonus: a few nullability fixes and extra `-v` logging.
Fixes https://github.com/flutter/flutter/issues/132654
Support for FFI calls with `@Native external` functions through Native assets on Windows. This enables bundling native code without any build-system boilerplate code.
For more info see:
* https://github.com/flutter/flutter/issues/129757
### Implementation details for Windows.
Mainly follows the design of https://github.com/flutter/flutter/pull/134031.
Specifically for Windows in this PR is the logic for finding the compiler `cl.exe` and environment variables that contain the paths to the Windows headers `vcvars.bat` based on `vswhere.exe`.
Reland of #134031. (Reverted in #135069.) Contains the fix for b/301051367 together with cl/567233346.
Support for FFI calls with `@Native external` functions through Native assets on Linux. This enables bundling native code without any build-system boilerplate code.
For more info see:
* https://github.com/flutter/flutter/issues/129757
### Implementation details for Linux.
Mainly follows the design of https://github.com/flutter/flutter/pull/130494.
Some differences are:
* Linux does not support cross compiling or compiling for multiple architectures, so this has not been implemented.
* Linux has no add2app.
The assets copying is done in the install-phase of the CMake build of a flutter app.
CMake requires the native assets folder to exist, so we create it also when the feature is disabled or there are no assets.
### Tests
This PR adds new tests to cover the various use cases.
* packages/flutter_tools/test/general.shard/linux/native_assets_test.dart
* Unit tests the Linux-specific part of building native assets.
It also extends various existing tests:
* packages/flutter_tools/test/integration.shard/native_assets_test.dart
* Runs (incl hot reload/hot restart), builds, builds frameworks for Linux and flutter-tester.
Reverts flutter/flutter#134031
context: b/301051367
Looked at the error message from the broken TAP target, but seems like the failure might be non trivial to resolve. Would it be okay if we revert this for now while it is being triaged?
Support for FFI calls with `@Native external` functions through Native assets on Linux. This enables bundling native code without any build-system boilerplate code.
For more info see:
* https://github.com/flutter/flutter/issues/129757
### Implementation details for Linux.
Mainly follows the design of https://github.com/flutter/flutter/pull/130494.
Some differences are:
* Linux does not support cross compiling or compiling for multiple architectures, so this has not been implemented.
* Linux has no add2app.
The assets copying is done in the install-phase of the CMake build of a flutter app.
CMake requires the native assets folder to exist, so we create it also when the feature is disabled or there are no assets.
### Tests
This PR adds new tests to cover the various use cases.
* packages/flutter_tools/test/general.shard/linux/native_assets_test.dart
* Unit tests the Linux-specific part of building native assets.
It also extends various existing tests:
* packages/flutter_tools/test/integration.shard/native_assets_test.dart
* Runs (incl hot reload/hot restart), builds, builds frameworks for Linux and flutter-tester.
Speeds up the native assets target in the backend by
1. changing other targets `gen_dart_plugin_registrant` and
`release_unpack_ios` to do async I/O,
2. not reparsing the package config, and
3. not calling `dart pub deps --json` for 0 or 1 packages (fixed
package:native_assets_builder).
* https://github.com/flutter/flutter/issues/134427
```
[ +2 ms] native_assets: Starting due to {}
[ +2 ms] Skipping target: gen_localizations
[ +1 ms] gen_dart_plugin_registrant: Starting due to {InvalidatedReasonKind.inputChanged: The following inputs have updated contents: /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/package_config_subset}
[ +33 ms] gen_dart_plugin_registrant: Complete
[ +107 ms] release_unpack_ios: Complete
[ +60 ms] Writing native_assets.yaml.
[ +7 ms] Writing /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/flutter_build/be2692bbfbc0b9a27fcd2422d52354c6/native_assets.yaml done.
[ ] native_assets: Complete
```
->
```
[ +4 ms] native_assets: Starting due to {}
[ ] Skipping target: gen_localizations
[ +1 ms] gen_dart_plugin_registrant: Starting due to {InvalidatedReasonKind.inputChanged: The following inputs have updated contents: /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/package_config_subset}
[ +31 ms] Writing native_assets.yaml.
[ +8 ms] Writing /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/flutter_build/f9451a65a465bfab70d004e21d6cc1d6/native_assets.yaml done.
[ +1 ms] native_assets: Complete
```
## Pre-launch Checklist
- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.
<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat
Support for FFI calls with `@Native external` functions through Native assets on MacOS and iOS. This enables bundling native code without any build-system boilerplate code.
For more info see:
* https://github.com/flutter/flutter/issues/129757
### Implementation details for MacOS and iOS.
Dylibs are bundled by (1) making them fat binaries if multiple architectures are targeted, (2) code signing these, and (3) copying them to the frameworks folder. These steps are done manual rather than via CocoaPods. CocoaPods would have done the same steps, but (a) needs the dylibs to be there before the `xcodebuild` invocation (we could trick it, by having a minimal dylib in the place and replace it during the build process, that works), and (b) can't deal with having no dylibs to be bundled (we'd have to bundle a dummy dylib or include some dummy C code in the build file).
The dylibs are build as a new target inside flutter assemble, as that is the moment we know what build-mode and architecture to target.
The mapping from asset id to dylib-path is passed in to every kernel compilation path. The interesting case is hot-restart where the initial kernel file is compiled by the "inner" flutter assemble, while after hot restart the "outer" flutter run compiled kernel file is pushed to the device. Both kernel files need to contain the mapping. The "inner" flutter assemble gets its mapping from the NativeAssets target which builds the native assets. The "outer" flutter run get its mapping from a dry-run invocation. Since this hot restart can be used for multiple target devices (`flutter run -d all`) it contains the mapping for all known targets.
### Example vs template
The PR includes a new template that uses the new native assets in a package and has an app importing that. Separate discussion in: https://github.com/flutter/flutter/issues/131209.
### Tests
This PR adds new tests to cover the various use cases.
* dev/devicelab/bin/tasks/native_assets_ios.dart
* Runs an example app with native assets in all build modes, doing hot reload and hot restart in debug mode.
* dev/devicelab/bin/tasks/native_assets_ios_simulator.dart
* Runs an example app with native assets, doing hot reload and hot restart.
* packages/flutter_tools/test/integration.shard/native_assets_test.dart
* Runs (incl hot reload/hot restart), builds, builds frameworks for iOS, MacOS and flutter-tester.
* packages/flutter_tools/test/general.shard/build_system/targets/native_assets_test.dart
* Unit tests the new Target in the backend.
* packages/flutter_tools/test/general.shard/ios/native_assets_test.dart
* packages/flutter_tools/test/general.shard/macos/native_assets_test.dart
* Unit tests the native assets being packaged on a iOS/MacOS build.
It also extends various existing tests:
* dev/devicelab/bin/tasks/module_test_ios.dart
* Exercises the add2app scenario.
* packages/flutter_tools/test/general.shard/features_test.dart
* Unit test the new feature flag.
PR provides a new option to the `test` command to include coverage info of specified packages.
It helps collecting coverage info in test setups where test code lives in separate packages or for multi-package projects.
At present, only current package is included to the final report.
Usage:
Consider an app with two packages: `app`, `common`.
Some of the tests in `app` use (indirectly) code that is located in `common`. When running with `--coverage` flag, that code is not included in the coverage report by default. To include `common` package in report, we can run:
```sh
flutter test --coverage --coverage-package app --coverage-package common
```
Note that `--coverage-package` accepts regular expression.
Fixes https://github.com/flutter/flutter/issues/79661
Fixes https://github.com/flutter/flutter/issues/101486
Fixes https://github.com/flutter/flutter/issues/93619
Roll to engine to 4f4486b00be28183b482bbb74bbed25f4db153fe pick up dart to 3.1.0-169.0.dev.
Changes since last roll
```
4f4486b00b Roll dart to 3.1.0-169.0.dev (#42602)
```
Manual roll since rolling to dart 3.1.0-169.0.dev requires patching to expression evaluation in flutter tools
Replace imports of `src/remote_listener.dart` with `backend.dart` which exports `RemoteListener`.
Remove the unused imports of `src/backend/stack_trace_formatter.dart` (no uses of `StackTraceFormatter`) and
`src/backend/suite_channel_manager.dart` (no uses of `SuiteChannelManager`).
The latest version of `test_api` removed the deprecated annotation for a couple libraries. The deprecations had been a hack to avoid usage from inappropriate places, but they cause trouble and likely weren't effective for that goal.
Remove separate import for `registerException` since that was also moved to be available from the top level `scaffolding.dart` library.
`flutter test` wasn't awaiting the `_serveObservatory` request which was
causing a race condition in the `flutter test should respect
--serve-observatory` test in `test/integration.general/test_test.dart`.
Related to https://github.com/flutter/flutter/issues/123516
