* Api Samples and Diagrams for the following classes and methods:

  - AlertDialog
  - SimpleDialog
  - SingleChildScrollView
  - showDatePicker
  - RichText
  - InputDecoration
  - Divider
  - StreamBuilder
  - DataTable
  - BottomSheet
    - showBottomSheet
    - showModalBottomSheet

* Update packages/flutter/lib/src/material/divider.dart
Co-Authored-By: Kate Lovett <katelovett@google.com>

* Update packages/flutter/lib/src/widgets/basic.dart
Co-Authored-By: Kate Lovett <katelovett@google.com>

* Update packages/flutter/lib/src/material/data_table.dart
Co-Authored-By: Kate Lovett <katelovett@google.com>

* Update packages/flutter/lib/src/material/bottom_sheet.dart
Co-Authored-By: Kate Lovett <katelovett@google.com>

* Update packages/flutter/lib/src/material/scaffold.dart
Co-Authored-By: Kate Lovett <katelovett@google.com>

* Move animation out of sample

* Remove "widget.size", replace with "60"

* 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

This PR adds TargetPlatform.macOS to the TargetPlatform enum. This allows us to begin implementation of some adaptive UI based on which target platform is desired.

I haven't updated the tests here, that will come in a follow-up PR.

* Added new ButtonBarTheme to replace the deprecated ButtonTheme.bar method.

* Responding to PR feedback.

* [Material] Create material Banner component (#36880)

This PR creates a new material widget for the Banner component. This includes a theme as well. This widget can be dropped into any application, ideally at the top of a listview or scrollview.

(cherry picked from commit 35b6d668)

Removed the use of ButtonTheme.bar in the Banner implementation.

* Updated documentation from PR review comments.

* more ui-as-code

* address review comments

Fixed several layout issues with the material date picker. Mostly just removed hard coded sizes to allow the grid view to scroll instead of overflowing.

* 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

Breaks the moveBy call from drag and dragFrom into two separate calls and changes the default behavior of DragStartBehavior to DragStartBehavior.start (#26438)

* Breaking change which sets the default DragStartBehavior to DragStartBehavior.start and changes WidgetTester.drag and WidgetTester.dragFrom by breaking the moveBy function call into multiple pieces.

* the onStart callback will report the location of the pointer where it wins the gesture arena by default instead of the pointer down location. Fixes all tests related to changing this default value.

* Force DatePicker value to stay within firstDate and lastDate upon year change

* updated per review feedback

This reverts commit 08538f91.

* Adds start behavior option to the drag gesture recognizer and makes it the default option when a drag gesture recognizer is created. Also fixes all the tests to work correctly with the new default behavior.

This reverts commit 80f80ab0.

For G3 Roll:

* Revert "MaterialButton must honor its minWidth and height parameters (#22919)"

This reverts commit a0233233.

* Revert "Update uses of ButtonTheme.bar: pass along the current Theme's colorScheme (#22827)"

This reverts commit 655bf6a2.

* Revert "ButtonTheme.of().colorScheme defers to Theme (#22880)"

This reverts commit a590940e.

* Revert "Bring TextTheme into alignment with the current Material spec (#22330)"

This reverts commit 8bfb4b3e.

* Revert "Added ColorScheme, updated ThemeData, ButtonTheme, material buttons (#22013)"

This reverts commit eea3465a.

* Manual adjustments to fix reversion issues.

ButtonThemeData no longer requires a colorScheme. If colorScheme is null, ButtonTheme.of() will initialize it from the current Theme.

* Update uses of ButtonTheme.bar

* updated gallery themes

* Remove unnecessary const

Fixes #22789

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

This reverts commit cc1cf13e.

* Chevrons in month picker are semi-transparent when the month is scrolled

* Added type missing annotation

fuchsia_tester.dart still assumes Dart 1. Previously, it ran tests directly
from source, flutter_platform.dart automatically runs a kernel compile when
operating in Dart 2 mode, but this assumes a functional Dart SDK is available
in the artifacts directly, and fuchsia_tester.dart mocks out the artifacts
directory with an empty temp dir.

Remaining work is:
1. Get the frontend server building as a dependency on Fuchsia.
2. Patch fuchsia_tester.dart to use a valid Dart SDK and frontend server.

This also reverts migration to Dart 2 typedef syntax.

This reverts commit 6c56bb24. (#18362)
This reverts commit 3daebd05. (#18316)