[a11y] Make sure RenderFractionalTranslation updates its semantics after the translation field is set (#48985)

* 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

* Extract some onPress methods

* address review comments

- Fixed the bug where CupertinoRefreshControl doesn't work in the gallery demo on Android.
- Updated documentation on CupertinoRefreshControl
- Added comments to the gallery demo
- Added concrete examples to ScrollPhysics

* fix some formatting issues

* address review comments

* fix indent

* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

Add a countdown timer picker as part of the Cupertino date picker.

Allows the cupertino picker to be scroll infinitely by adding builder.

It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)