I'm working on fixing up all tests that rely on fs.currentDirectory to allow us to run concurrently. This one proved to be really tricky because it calls a lot of code and spawns multiple processes that have a mix of absolute and relative paths passed to them. I managed to handle some of it with a ChrootFileSystem, but the paths passed to the external processes were wrong.

The functionality here is covered by all of the integration tests that use flutter_tester that were added after this, including flutter_run_test.dart, lifetime_test.dart etc. in this same folder but because they're run through `flutter run` as a separate process they get to set their own working directories without affecting other tests if run concurrently.

The average frame time of page transitions on Moto G4 is now very
close to 16ms (the last 10 measurements on our dashboard are
between 15.5ms to 16.7ms and half of them are below 16ms).

It is now much faster than when we disabled it (which was at about
35ms). So I think that we should be able to enable it by default.
I'll leave the flag there until we implement the retained rendering
to bring the frame time comfortably below 16ms.

See https://github.com/flutter/flutter/issues/13736

Setting the default clip behavior made bottom app bar to no longer clip
its children.
With this parameter users could opt-in to clipping.

* Add a detach command to detach without terminating (#21376)

* Add a detach command to detach without terminating

Fixes #21154.

* Bump protocol version for app.detach

* Tweak to detach/quit text

* Change logPrefix to named param

* Fix the text that the devicelab attach test looks for

* Rename test file

* Fix detection to work regardless of whether there are other devices

On Windows we get one message, but on Mac we get another (because of the Simulator always being available).

Revert "Allow FlutterTester to be provided with the working directory for execution (#21119)" (#21453)

This reverts commit 857bdc7a.

* Allow FlutterTester to be provided with the working directory for execution

Previously this test set fs.currentDirectory which prevents running tests concurrently. This allows setting the working directory for a FlutterTester in the cosntructor (optionally) and passes it through from the test (without setting fs.currentDirectory).

* Remove trailing whitespace

* Add a detach command to detach without terminating

Fixes #21154.

* Bump protocol version for app.detach

* Tweak to detach/quit text

* Change logPrefix to named param

Move asset_bundle_package_test to MemoryFileSystem to avoid setting fs.currentDirectory in tests (#21427)

* Update asset_bundle_package_test to use MemoryFileSystem

This updates all tests in this file to use a memory filesystem (same as I did for asset_bundle_package_font_test) based on the current platform.

There were already a few minor tests at the bottom using a MemoryFileSystem and being run for all platforms - however this complicated the shared code I changed above to support Windows natively so I changed them to also work the same as others (that is, they just run the native platforms so require running on all to get full coverage - though this is the case for almost all other tests anyway).

* Move fixPath to the correct place

* Add a failing test for #21418

* Filter workflows to only those applicable to the current platform

Fixes #21418.

* First step in Flutter Doctor refactor. Assigns categories to all validators.

* Revert "Roll engine e54bc4ea1832..a84b210b3d26 (6 commits) (#20453)"

This reverts commit 05c2880a.

* Split iOS and Android workflows into workflow and validator classes.

* Change ValidatorCategory to handle standalone validators that share a
category (e.g. IntelliJ).

Also make Android Studio and Android toolchain use separate categories.

At this stage, flutter doctor output matches what it was previously.
(The summary() method itself has not yet been changed )

* Change doctor summary code to support validator categories.

Output is still unchanged.

* Handle small formatting issues.

* Flip Flutter category's isGroup field to false until it's actually
needed.

* Revert auto-generated formatting changes to keep those lines from
muddying the pull.

* Small fixes pointed out by analyzer.

* Properly fix analyzer issues around const constructors.

* Small changes to address comments.

* Add tests to verify grouped validator behavior and validationtype
merging.

* Update doctor.dart

* Add comments for clarification.

* Added size to stepper icons

* Added Stepper icons size test

Dart 1 is no longer supported in Flutter. Hot reload now always occurs
via kernel file updates (plus any asset bundle changes).

Closes #3188

Dart 1 is no longer supported in Flutter.

This reverts commit 3306fc10.

Enable taking screenshots of arbitrary RenderObjects from a running application from within the inspector.

Key functionality is in the added _ScreenshotPaintingContext class.

Script snapshots were only every used in Dart 1 mode, which is no longer
supported.

Added InheritedModel:  An InheritedWidget that's intended to be used as the base class for models whose dependents may only depend on one part or "aspect" of the overall model.

* Change assert_bundle_package_font_test to memory file system

This is to work towards being able to run the tests without `-j1` (#21113). These tests were using the real filesystem and setting/relying on fs.currentDirectory. There was a comment about this being because the memory provider didnt' support POSIX and Windows, however that seems to have changed since (and many other asset tests already do something similar to this).

* Trim trailing whitespace

* Add a workaround for Windows path slash directions

Strictly this is correct, but the real FS can tolerate either path. The in-memory file system is more strict (see https://github.com/google/file.dart/issues/112).

* Extract a helper for writing schema files in tests

* Missed file when saving!

* Remove redundant comment

* Rename writeBasicSchema -> writeEmptySchema

* Use the file we already have to write contents

* Make comments more descriptive

* Remove another dupe of writeSchema to use the shared one

* Rename schema -> pubspec_schema

* Trim whitespace

This patch eliminates the --preview-dart-2/--no-preview-dart-2 flag,
hardcoding all uses to true. It also defaults all previewDart2 method
parameters to true, where they hadn't yet been.

A series of subsequent patches will eliminate all previewDart2
parameters and the associated code from within the codebase.

* Unskip integration tests on Windows that now pass

The referenced issue is closed and these tests pass for me locally on Windows now.

* Remove import that's no longer used

* Add another issue that is afffecting these tests on Windows

* Add a hot restart test and mark skip on Windows

Skipped due to https://github.com/flutter/flutter/issues/21348.

https://github.com/flutter/engine/compare/77fad1a731f2...de4c7a53f21c

git log 77fad1a731f2..de4c7a53f21c --no-merges --oneline
de4c7a53f Roll src/third_party/skia 09a7bb222172..88119de2b849 (1 commits) (flutter/engine#6146)


The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
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If the roll is causing failures, please contact the current sheriff, who should
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https://github.com/flutter/engine/compare/2318a5274af4...77fad1a731f2

git log 2318a5274af4..77fad1a731f2 --no-merges --oneline
77fad1a73 Roll src/third_party/skia 2f53025e8bf1..09a7bb222172 (1 commits) (flutter/engine#6144)


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https://github.com/flutter/engine/compare/d88e0b8229ec...2318a5274af4

git log d88e0b8229ec..2318a5274af4 --no-merges --oneline
2318a5274 Roll src/third_party/skia ca858b68c34b..2f53025e8bf1 (1 commits) (flutter/engine#6143)


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https://github.com/flutter/engine/compare/949fb0fb4cbe...d88e0b8229ec

git log 949fb0fb4cbe..d88e0b8229ec --no-merges --oneline
d88e0b822 Roll src/third_party/skia 2f8c60e28682..ca858b68c34b (2 commits) (flutter/engine#6142)


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