fuchsia_tester.dart still assumes Dart 1. Previously, it ran tests directly
from source, flutter_platform.dart automatically runs a kernel compile when
operating in Dart 2 mode, but this assumes a functional Dart SDK is available
in the artifacts directly, and fuchsia_tester.dart mocks out the artifacts
directory with an empty temp dir.

Remaining work is:
1. Get the frontend server building as a dependency on Fuchsia.
2. Patch fuchsia_tester.dart to use a valid Dart SDK and frontend server.

This also reverts migration to Dart 2 typedef syntax.

This reverts commit 6c56bb24. (#18362)
This reverts commit 3daebd05. (#18316)

Now that Dart 1 is turned off, reapplying my change to turn on the prefer_generic_function_type_aliases analysis option, and fix all the typedefs to Dart 2 preferred syntax.

Also eliminated the unused analysis_options_repo.yaml file and turned on public_member_api_docs in analysys_options.yaml.

No logic changes, just changing the typedef syntax for all typedefs, and updating analysis options.

Revert "Update typedef syntax to use Function notation and turn on lint for old notation. (#18035)" (#18041)

This reverts commit 32586020.

Fixes #18028

Just changes typedef declarations, no logic changes.

https://github.com/dart-lang/pub/issues/1812

* Change the default for pub tracing to false for non-bot runs

* Review feedback: update docs

* Review feedback

Adds a class `PubContext` with a fixed set of allowed values
Make it clear these values should not be changed casually

Fixed one inconsistency already: update_packages vs update_pkgs
Provide more information for verify calls
Eliminate `ctx_` prefix.

The purpose of this PR is to make it so that when the user runs 'flutter', if they have a .pub-cache directory in their flutter root, we use that instead of the default location for the pub cache. Otherwise, it should act as before.

The eventual goal is to support a pre-populated flutter .zip/.tar.gz file that has everything the developer needs in one bundle. In order for that to actually work, we need to have the pub cache be self-contained, and not in the user's home dir.

Another advantage of this is that if you have multiple flutter repos that you're switching between, then the versions in the pub cache will remain static when you switch between them.

This is an attempt to re-land: #13248. Includes a fix for the test that makes it work on bots in the presence of PUB_CACHE being set, and no other changes.

* Revert "Add tests."

This reverts commit 31bad961ff2220a2708917ff8f748fed7efa9b51.

* Revert "Use .pub-cache from Flutter root, if it exists. (#13248)"

This reverts commit 72d6bcc3.

The purpose of this PR is to make it so that when the user runs 'flutter', if they have a .pub-cache directory in their flutter root, we use that instead of the default location for the pub cache. Otherwise, it should act as before.

The eventual goal is to support a pre-populated flutter .zip/.tar.gz file that has everything the developer needs in one bundle. In order for that to actually work, we need to have the pub cache be self-contained, and not in the user's home dir.

Another advantage of this is that if you have multiple flutter repos that you're switching between, then the versions in the pub cache will remain static when you switch between them.

* Provide more information in PUB_ENVIRONMENT for `pub get/upgrade`

Should help diagnose and fix https://github.com/dart-lang/pub-dartlang-dart/issues/636

See https://github.com/dart-lang/pub/issues/1714

* Teach flutter_tools to populate PUB_ENVIRONMENT

Will allow telemetry reporting on pub.dartlang.org once
flutter moves to 1.23.0-dev.10.0

* review changes

* improve the logger ui a bit for elapsed times

* invert param

* update daemon.dart

This removes direct file access from within flutter_tools
in favor of using `package:file` via a `FileSystem` that's
accessed via the `ApplicationContext`.

This lays the groundwork for us to be able to easily swap
out the underlying file system when running Flutter tools,
which will be used to provide a record/replay file system,
analogous to what we have for process invocations.

* convert pubGet to throw ToolExit on non-zero exit code
* convert commandValidator to throw ToolExit for non-zero exit code
* convert flutter commands to throw ToolExit for non-zero exit code
* use convenience method throwToolExit
* only show "if this problem persists" for unusual exceptions

* make showElapsedTime default to true

* support nested progresses

* improve hot reload message

* rethrow

Fixes #6417

* suppress warning; decouple the analyzer versions

* also pass in --no-packages-dir

* Udpate to Dart `1.20.0-dev.1.0`.

Udpate to Dart `1.20.0-dev.1.0` and corresponding `analyzer` package.

* Added `--no-packages-dir`.

* Revert extension to master.

* Added ignores.

* Review nits.

* More nits.

* use vendored dart sdk; check the expected version of flutter

* search up directories looking for the flutter root

* have flutter precache print if there's no work to do

* tweak precache

This will help folks run pub get after they upgrade their flutter.git
revision.

* use --no-precompile

* use the flutter bin cache's sdk

Also, resolve our package conflict, since reflectable has been fixed.

Now that we don't require the Dart SDK to be in your path, it's hard to run
./dev/update_packages.dart. Instead, you can now run `flutter update-packages`.

Fixes #1906