30+4 has made some changes to the remoting protocol that are incompatbile
with a test harness running 30+3 (e.g. adding a type='initial' field to the
first message)

* All lists produced by JSON parsing are List<dynamic>. If more
speficic type is required then they need to be explicitly cast, e.g.
using castFrom helper;
* Function of type (ByText) -> Finder is not a subtype of
(SerializableFinder) -> Finder because ByText is in the contravariant
position;
* In Dart 2 typed(any) should be used instead of any in mockito based
tests.

* Use engine-built dart sdk

* Download dart-sdk from engine

* Move up deps to fix dart sdk constraint problem

* Update update_dart_sdk.ps1 for Windows

* Fix tests so they pass analysis

* More types for tests

* Roll engine

* Update dart sdk stamp location in flutter.bat

* Add newline

We need to pull in Dart 2 compliant mockito

Fixes #14532

There were some problems I introduced with the last PR for this. It passed the test, but failed in practice.

This adds tests for those failure cases, adds a "--help" and fixes the test so that it doesn't try and actually download MinGit as part of the Windows test.

I added package:platform as a dependency, so I did a force upgrade on the packages.

Also, re-enabling 'create package' in the cache warming code, now that #14448 is fixed.

* Unpin package:test and upgrade packages

* Update packages/flutter/test/foundation/stack_trace_test.dart

* Also add packages/flutter_tools/test/data/asset_test/font/.dartignore to ensure that update-packages --force-upgrade does not crash.

Generate the "version" file from git tags.
Remove the old VERSION file and mentions of versions in pubspec.yaml files.
Replace the old update_versions.dart script with a new roll_dev.dart script.
Update "flutter channel".
Update "flutter upgrade", including making it transition from alpha to dev.
Update "flutter --version" and "flutter doctor".

Rolling the Dart SDK to 2.0, with associated package updates.  

https://groups.google.com/forum/#!topic/flutter-dev/E22RdKAYjs8

* Revert "Reverting package changes until I can figure out how to fix Windows. (#14007)"

This reverts commit 6fda8ee8.

* Make prepare_package run on Windows

* Revert "Fixed output validation. (#14005)"

This reverts commit d84398db.

* Revert "Update package prep script to do async process execution and emit output as it happens. (#13918)"

This reverts commit b7169c1d.

 - Switches to async process execution, which now shows output as it happens instead of in chunks when the process completes
-  Now uses ProcessManager so that it may be mocked for the test.
- Adds in the download and install of mingit on Windows.
- Updated package dependencies because of added dependency on process package.

This simply updates the package dependencies by running flutter update-packages --force-upgrade.

I'm doing this with no other changes, because the last time I tried that, redness occurred. I want to isolate the problem to a "clean" update of the packages.

It looks like the plugins device_info, connectivity, and url_launcher haven't yet had their gradle configurations updated, so they fail when trying to build with the new gradle. I did not upgrade for those three packages only (in flutter_gallery) until we are ready to fix them (fixing them for master will break them for alpha users, so we need to do an alpha roll to do that).

This reverts commit 765191e7.
because the updated packages cause a gradle build problem.

This adds our self-compiled copy of the MinGit executable (built from the flutter/git repo) to the archive when building an archive for Windows.

I also tweaked the internal API for prepare_package.dart so that there's a single entry point to build an archive.

* Change async stubbing to use thenAnswer.

Mockito now prohibits calling thenReturn with Futures and Streams. dart-lang/mockito#79

* Update all Mockito deps to 3.0.0.

* Revert "Update all Mockito deps to 3.0.0."

This reverts commit e8ab9d37c33d3d7fe384abde64ea5b4d72623c75.

I did not correctly update the mockito dep, and there's no easy way to update to 3.0 alpha right now.

* Change thenAnswer((_) => to thenAnswer((invocation) =>

* Add Invocation type to thenAnswer lambdas

* flutter update-packages

* update plugin registrant for flutter_gallery

Updating SDK and package versions now that alpha has been rolled to 0.0.20

This allows the scheduler library to depend on the services library
and the painting library to depend on the scheduler library without
the services library having to depend on the scheduler library.

While I was at it I also cleaned up some of the binding logic: the
licenses logic can now be overridden (and the test library does so),
and the image cache can now be overridden as well.

* Emulate text entry in FlutterDriver

* document enterText behavior

* remove the unnecessary composint TextRange

Updates quiver from 0.26.0 to 0.26.2 to pick up strong-mode fixes.

This patch reorganises flutter_driver's lib/src directory into three
subdirectories:

* driver: sources transitively imported/exported by flutter_driver.dart,
  which defines the API used by driver tests executed on the host machine.

* extension: sources transitively imported/exported by
  driver_extension.dart, which defines the API used to instrument a
  Flutter app running on the target device for use with a driver test.

* common: sources common to both driver and extension code.

This makes rolling Flutter into repositories that use Bazel (or
Bazel-like build systems) significantly more robust, due to the simpler
glob patterns involved.

Use of this file was eliminated in e7657b94.

* clear timeline events prior to starting a new action

* trailing commas

1. We want to measure wall-clock duration for the benchmarks, as opposed
   to thread duration (e.g., waiting on a mutex should accrue time) and
   'dur' is the metric to use for that.

2. On Darwin-based systems (macOS and iOS) 'tdur' is the result of a
   mach syscall lookup to thread_info. This call returns unreliable data
   on iOS. Chromium, for example, disables thread time support entirely
   for iOS.