* Added support for authentication codes for the VM service.

Previously, a valid web socket connection would use the following URI:

`ws://127.0.0.1/ws`

Now, by default, the VM service requires a connection to be made with a
URI similar to the following:

`ws://127.0.0.1:8181/Ug_U0QVsqFs=/ws`

where `Ug_U0QVsqFs` is an authentication code generated and shared by
the
service.

This behavior can be disabled with the `--disable-service-auth-codes`
flag.

This reverts commit 19d6e7b6.

This renames the "module" template to the "application" template, and makes "application" the default. The existing "app" template is now deprecated.

flutter create also now recognizes the type of project in an existing directory, and is able to recreate it without having the template type explicitly specified (although you can still do that). It does this now by first looking in the .metadata file for the new project_type field, and if it doesn't find that, then it looks at the directory structure. Also, the .metadata file is now overwritten even on an existing directory so that 1) the project_type can be added to legacy projects, and 2) the version of Flutter that updated the project last is updated.

I also cleaned up a bunch of things in create_test.dart, added many more tests, and added an example test to the test/ directory in the generated output of the application template.

Fixes #22530
Fixes #22344

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

Apparently Gradle leaks memory and it's causing failures.

* Fix TODO syntax.
* Clarify messages for some timeouts, to aid debugging.
* Increase some other timeouts that were a needlessly short, to reduce sources of flakes.
* Remove some more timeouts that were mostly redundant, to remove complexity.
* Minor style cleanup.
* Remove some dangerous traps (specifically, hide the explicit start/end times in TimedEvent since they shouldn't matter).

It was causing problems rolling Flutter into Fuchsia

* 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

This reverts commit cc1cf13e.

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 is an attempt to reland #18488 with less breakage on macOS.

This reverts commit 77508722.

The new values are not ready for use yet inside Google

* Roll engine to e976be13c51448f89107d082ec81e2b6731671fa

* move away from deprecated constants

This reverts commit f40a9398.

Fixes https://github.com/flutter/flutter/issues/7661

...now that we have generic methods, their types need to be specified too.

* fix flutter watch benchmark

Syncs https://github.com/flutter/cocoon/commit/d2d7950ecd2c72421d75d9b5d54805cc554e92a8

* Split Android/iOS impl behind a unified interface

Syncs https://github.com/flutter/cocoon/commit/db87e10fa54317115479d0b85280c7e5eed08ff7

* Switch from pub get to flutter packages get

Syncs https://github.com/flutter/cocoon/commit/b378005cbbc5330058d5240a2970ca477c2c9722

* "silent" option in test runner; fix analysis errors;