Make Element tree root generic

Update ScrollableDetails for 2D scrolling

* Rename WindowPadding to ViewPadding

* dart fix

* typos

* lerp documentation

* Remove Note, Note That from repo

* Improve BorderSide documentation.

* apply review comments

* Deprecate MediaQuery[Data].fromWindow

* ++

* dart fix

* Remove deprecated AnimatedSize.vsync parameter

* add dartfix

* Update packages/flutter/lib/fix_data/fix_widgets/fix_widgets.yaml

* Update packages/flutter/lib/fix_data/fix_widgets/fix_widgets.yaml

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Co-authored-by: Kate Lovett <katelovett@google.com>

* Refactor fix_data.yaml

* ++

* lib, not lib/src

* Nit

* Nit

* Update packages/flutter/test_fixes/material/app_bar_theme.dart
Co-authored-by: Alexander Dahlberg <dustbin4ever@gmail.com>

* Fix copy paste errors
Co-authored-by: Alexander Dahlberg <dustbin4ever@gmail.com>