* Co-authored-by: Brett Morgan <brettmorgan@google.com>

* 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.

* Added customizable drawer edge drag width parameter to Drawer and Scaffold

* Fix Drawer drag area width for notched devices

* Update Drawer tests to reflect necessary LTR and RTL Drawer edge widths

* Add images and update examples for top widgets:

  - scaffold
  - text field
  - image
  - text
  - row
  - column
  - stack

* more ui-as-code

* address review comments

* WIP

* Added tests and updated SafeArea implementation.

* Analyzer nits

* Review feedback

* Updated for SnackBar and PersistentFooterButton cases, added tests to check other potential spots.

* doc addition for SafeArea

* Typos

* Introduce BottomSheetTheme and shape support for bottom sheet

* Add bottom sheet theme to ThemeData. Use theme in bottom sheet build

* Expose color, elevation, shape to showModalBottomSheet helper

* Expose color, elevation, shape to showBottomSheet helper

* Address PR feedback

* Address PR feedback

* Address additional PR feedback

This PR introduces a number of changes and improvements to snack bars. This includes the ability to specify:

floating style of snack bars that adhere to the updated Material spec
elevation and shape on the SnackBar itself instead of relying on fixed values
a snackBarTheme as part of ThemeData which allows you to customize all of the above on an app-wide level.
This PR is includes the changes from #21484 as well as additional fixes and modifications. Thanks to @NikoYuwono for providing these changes and getting this off the ground!

* some space formattings

* always use blocks in if-else if a block is used

* format spaces in for and while

* allow multiline if conditions

* fix missing space

* 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

Fix the spelling errors in the dartdocs for the framework.

There are no functionality changes here, just documentation fixes.

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.

This converts all remaining "## Sample code" segments into snippets, and fixes
the snippet generator to handle multiple snippets in the same dartdoc block
properly.

I also generated, compiled, and ran each of the existing application samples,
and fixed them up to be more useful and/or just run without errors.

This PR fixes these problems with examples:

1. Switching tabs in a snippet now works if there is more than one snippet in
   a single dartdoc block.
2. Generation of snippet code now works if there is more than one snippet.
3. Contrast of text and links in the code sample block has been improved to
   recommended levels.
4. Added five new snippet templates, including a "freeform" template to make
   it possible to show examples that need to change the app instantiation.
5. Fixed several examples to run properly, a couple by adding the "Scaffold"
   widget to the template, a couple by just fixing their code.
6. Fixed visual look of some of the samples when they run by placing many
   samples inside of a Scaffold.
7. In order to make it easier to run locally, changed the sample analyzer to
   remove the contents of the supplied temp directory before running, since
   having files that hang around is problematic (only a problem when running
   locally with the `--temp` argument).
8. Added a `SampleCheckerException` class, and handle sample checking
   exceptions more gracefully.
9. Deprecated the old "## Sample code" designation, and added enforcement for
   the deprecation.
10. Removed unnecessary `new` from templates (although they never appeared in
   the samples thanks to dartfmt, but still).

Fixes #26398
Fixes #27411

* Add more animation tests for rotation

* Test animation progress

* Progress on the tests

* Everything 'works'

* We don't need to guarantee the rotation of the fab as it exits.

* Remove print statement

* Cleanup extra lines

* Remove whitespace

Generally, we should always use default-less switches for
platform-specific behaviour so we're forced to make a conscious decision
on each instance of such behaviour any time we add support for a new
platform.

* 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.

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.

Top left and top right for big FABs, and top left for mini FABs.

Upgraded Scaffold example to an application example.

This converts existing ## Sample code samples to {@tool sample}...{@end-tool} form.

Also:
1. Fixed a minor bug in analyze-sample-code.dart
2. Made the snippet tool only insert descriptions if the description is non-empty.
3. Moved the Card diagram to before the code sample.