These aren't needed anymore.

Switch our pubspec.yamls to using SDK sources so that we can have consistent
source types when we depend on these packages from external packages using SDK
sources.

This rewrites imports of various mojom.dart files from the Flutter
engine repo to instead import normal-looking dart files from the
(new) flutter_services package. This package handles exporting the
correct symbols from generated code wherever that may live.

Includes an engine roll to 3551e7a48e2e336777b15c7637af92fd7605b6c5
which contains the new flutter_services package.

* 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.

Prep to get us ready to pull in a new dev SDK and bump our analyzer DEP.

* updates `crypto` (required by fresh analyzer)
* fixes newly flagged dead code warnings
* fixes switches that fall through and don't return

Prep to get us ready to pull in a new dev SDK and bump our analyzer DEP.

* updates `crypto` (required by fresh analyzer)
* fixes newly flagged dead code warnings
* fixes switches that fall through and don't return

The new version has an API change. Also, up our SDK requirements to be a
bit more realistic.

Our microbenchmarks now run on real devices.

Cassowary doesn't have any additional dependencies and this simplifies things.

Fixes #2442

Rather that importing `package:newton/newton.dart` you can
`import package:flutter/physics.dart`.

Fixes #2441

With the new dev build we've got the updated linter and so can use the `@optionalTypeArgs` annotation (in `meta 0.12.0`).

Bonus: this lets us clean up one more Regexp in the `analyze` command! :)

The .packages file is replacing the packages directory of symlinks.

...so that we can shed the quiver dependency in flutter's framework.

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

We get the icons from the iconfont now.

Also, remove the package:flutter CHANGELOG.md.  This file is outdated and the
git history is a more accurate change log these days.

The mojo_sdk has cleaned up its dependencies, so we no longer need to depend on
package:test from package:flutter.

This patch switches us from using our previous hacking approach to integrating
with package:test to using the new PlatformPlugin interface.

See the comment in the patch for details.

Downloading these packages from cloud storage simplifies our deployment
story because we can upload to cloud storage automatically from the
buildbot.

This patch also switches the responsibility for downloading the engine
artifacts to update_engine.sh. Centralizing this responsibility ensures
that the packages and the binaries are always in sync.

This reverts commit b240cda8.

This reverts commit ab300634.

Third-party libraries can now provide their own mojo services. They do
so by adding a config.yaml file to their pub package which contains
- a list of service names and java classes which handles that service's
  registration.
- a list of pre-built .jar files to statically link with the app's shell
  when building the app.