On Android and Fuchsia, default to Roboto. On iOS, use San Francisco.

This is causing issues when integratting Flutter into GN as the
generated depfile refers to snapshot as the target instead of the
bundle. We instead use a separate GN action to generate the
snapshot use the Flutter compiler to only assemble the bundle.

* add flutter run --machine flag
* refactor daemon stdin/out command stream/response
* extract daemon startApp method
* refactor flutter run --machine to call daemon.startApp

* merge `flutter skia` into `flutter screenshot`
* improve skia failed error message
* update help text - how to find diagnostic port for skia
* improve error message if skia capture fails

FormField is now a widget that can contain any type of field. Input no
longer has special code to handle form fields. Instead, there is a
helper widget InputFormField for using an Input inside a FormField.

Fixes https://github.com/flutter/flutter/issues/6097 and based on
feedback from the same.

* Fix Missing newline in flutter run help
Issue #6461

* Fix overtab from multiline

Fixes https://github.com/flutter/flutter/issues/6280

Fixes #6417

* implement app.stop() for release runs

* update comment

* remove the validator check for atom

* remove the atom launch config

* review comments

Previously we weren't using all the different weights of the font.

Disable features of `flutter run` that depend on the service protocol when running in release mode (#6571)

TBR @abarth

...until people understand them.

Fixes #4166.
Fixes #5120.
Fixes #5399.
Fixes #6507.

Try to be clearer that flutter-dev is a public mailing list.

We now create the Completer inside TransitionRoute, as with the popped
completer. Also, test that this future resolves at the appropriate time.