* add shadowColor property

* add to bottom app bar

* add test

* update m2/m3 diffs

* reorder debug test

* finalize

* remove crswap

* update doc comments

* add m2 shadow back

* add const

* update docs

* update docs

* comment replies

* make param non-null

* indentation fix

* doc fix

* dart fix --apply

* manual fixes

* squash 5 into 1

fix

Update packages/flutter/lib/src/material/bottom_app_bar.dart

lint

update tests
Co-Authored-By: Hans Muller <hansmuller@chromium.org>

* lint
Co-authored-by: Hans Muller <hansmuller@chromium.org>

* Revert "Revert "Add Material 3 support for BottomAppBar" (#114421)"

This reverts commit 210a2aa3.

* Regenerated the defaults from tokens and fixed tests.

* Fixed the tests.

* Updated the shape token template to optimize the a common case.

* Use `curly_braces_in_flow_control_structures` for `material`

* include test/material

* add back removed comments

* migrates lib/foundation and lib/widgets

* migrates lib/painting and lib/material

* migrates lib/cupertino, lib/gestures, lib/services, lib/semantics and lib/rendering

* fixes failing tests

* migrates test/

* improves hashing of lists

This reverts commit 81439922.

* migrate some material files to nullsafety

* review

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag

This converts Diagnosticable to be a mixin instead of an abstract class, so that it can be used to add diagnostics to classes which already have a base class.

It leaves in place the DiagnosticableMixin mixin, since there are some plugins that are still using it, and removing it would mean that those plugins wouldn't work with master branch Flutter anymore. DiagnosticableMixin will be removed once this mixin version of Diagnosticable makes its way to the stable branch.

* implicit-casts:false in flutter/lib/src/material

* address review comments

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

* [WIP] BAB theme

* [WIP] BAB theme

* Update goldens

* Extract helper function in tests

* Update Goldens version

* Add tests

* [WIP] Hans first round comments

* Added test

* Added docs

* Hans second round comments

* Fixed analyzer error

* Hans third round comments

* ambient

* Change [BottomAppBarTheme.of] to static

* Final doc change