This reverts commit 38407199.

Bug: https://github.com/flutter/flutter/issues/19435

The trailing whitespace detector wasn't handling file deletes very well (at all, really).

This filters the set of files grepped to only include files that exist.

Also, clarified the failure message to make it more obvious what the failure is when the grep finds results.

* Fix the checksum verification to be more sensitive

* update packages

* Tell flutter to quit directly

Fixes #19208.

* Tweak comment

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

* Remove uses of deprecated constants
* Change int.parse to int.tryParse where appropriate

Checks only changed source files (C++, Dart, Java, ObjC) for trailing whitespace.

Generated.xcconfig is only required at build time for iOS apps. In the
flutter create project template and example apps, Generated.xcconfig was
previously marked as a resource to be bundled into the built app.

While working on attach, I changed the message output while waiting for an app to connect but didn't catch this.

Flutter app development has been Dart 2 only for a significant amount of
time, and we're about to remove all support for Dart 1.

Bug: https://github.com/flutter/flutter/issues/19435

This reverts commit cc1cf13e.

This uses @kevmoo's completion package to do command line completion for flutter, and a new command "bash-completion" (with alias "zsh-completion") that will output the necessary shell script setup code, and adds the hidden command "completion" that does the actual completion.

Because it adds a dependency, I also had to do flutter update-packages --force-upgrade.

Fixes #18988.

Revert "Revert "Roll engine to fed2ea458ed49088d33eddabc546ba56d600c717 (includes dart roll) again (#19277)" (#19295)" (#19322)

This reverts commit cc122f16.

Revert "Roll engine to fed2ea458ed49088d33eddabc546ba56d600c717 (includes dart roll) again (#19277)" (#19295)

This reverts commit 700cb767 as it
breaks Windows tests.

* Revert "Revert "Roll engine to fed2ea458ed49088d33eddabc546ba56d600c717 (includes dart roll) (#19044)" (#19276)"

This reverts commit cf932490 as it also
includes fix for type error that broke tests.

* Add type cast for dart2 type checks.

* Move up to latest goldens

* Make inDirectory() type-parameterized.

* Add typecasting to transitions_perf_test.dart and microbenchmarks.

* Add boolean flag initialization in save_catalog_screenshots.dart

* Add type conversion to gallery transition test

Revert "Roll engine to fed2ea458ed49088d33eddabc546ba56d600c717 (includes dart roll) (#19044)" (#19276)

This reverts commit f4a038da as it breaks microbenchmark tests.

* Roll engine to rolled dart
Add connectionTimeout property to class that extends HttpOverrides.
Upgrade packages.
Add more type fixes.
Update goldens hash.
Add more type fixes.
Upgrade packages.
Fix tests.
Remove strong-mode from analysis options yaml file.
Increase dev/devicelab timeout from 2 to 10 seconds.
Added getVM to waitForViews. Fix type errors in compileExpression.

* Pick up engine revision with fix for microbenchmarks regression.
Increase default timeout from 20/30 to 60s.

This should make it more obvious from the error what's gone wrong if we see a repeat of #19096 (previously the error was something like "Bad state: future already completed").

This reverts commit edc16473.

Await stream cancellations before trying to complete

* Include stdout/stderr in failure messages

Sometimes some of these tests unexpectedly fail with a non-zero exit code. This ensures stdout/stderr is included in the test failure message when this happens so that we can track down the issue.

* Remove redundant info about exit code

* Remove unnecessary indenting

The [markers] make it fairly clear so this just makes the test code noisy.