Clarified an assert for when a Material widget's backgroundColor is null when its type isn't MaterialType.transparency

* 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.

Add Material/Card borderOnForeground flag to allow border to be painted behind the child widget (#27297)

In certain situations, a developer may require the border of a Material to be painted behind its child. For example a Card widget that has a full width image across the top half. In that scenario, the image should ideally be painted above the border with regards to z-position.

This change exposes a flag on Material widget to achieve this behavior. Additionally, the same flag is exposed on Card widget to allow the Card widget to pass this down to its Material.

I added a couple golden tests to verify this new behavior. Goldens are here:
https://github.com/flutter/goldens/commit/46a3d26acbb1b0d72b6b02c30f03b9dbda7d5bdf

* Themable elevation on dialogs.

* Added `BackgroundColor` in widget + theme

* Addressing Comments

* Fix test name

* Add debugFillProperties test

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

This reverts commit 8de0e15e and
updates the goldens versoin.

This requires https://github.com/flutter/flutter/pull/20751 to
land first.

This fixes https://github.com/flutter/flutter/issues/18057

See details in our proposal for this breaking API change and #18057. This PR setup all code paths to allow the change but doesn't change the clip behavior by itself. We'll change `defaultClipBehavior` from `Clip.antiAlias` to `Clip.none` in the following PR to change the clip behavior and update tests.

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)

Now that Dart 1 is turned off, reapplying my change to turn on the prefer_generic_function_type_aliases analysis option, and fix all the typedefs to Dart 2 preferred syntax.

Also eliminated the unused analysis_options_repo.yaml file and turned on public_member_api_docs in analysys_options.yaml.

No logic changes, just changing the typedef syntax for all typedefs, and updating analysis options.

Revert "Update typedef syntax to use Function notation and turn on lint for old notation. (#18035)" (#18041)

This reverts commit 32586020.

Fixes #18028

Just changes typedef declarations, no logic changes.

* spelling: accommodate

* spelling: allotted

* spelling: anonymous

* spelling: artificial

* spelling: associated

* spelling: asset

* spelling: button

* spelling: canvas

* spelling: compatibility

* spelling: coverage

* spelling: condition

* spelling: decoration

* spelling: deferring

* spelling: diameter

* spelling: direction

* spelling: displacement

* spelling: dropdown

* spelling: needing

* spelling: environment

* spelling: exited

* spelling: expansion

* spelling: explore

* spelling: families

* spelling: horizontal

* spelling: increment

* spelling: indices

* spelling: internationalization

* spelling: labrador

* spelling: localizations

* spelling: midflight

* spelling: milliseconds

* spelling: minimum

* spelling: multiple

* spelling: multiplication

* spelling: navigator

* spelling: overridden

* spelling: package

* spelling: performance

* spelling: platform

* spelling: porsche

* spelling: position

* spelling: preceded

* spelling: precede

* spelling: precedence

* spelling: print

* spelling: property

* spelling: readily

* spelling: reproducibility

* spelling: rounded

* spelling: scroll

* spelling: separate

* spelling: separator

* spelling: services

* spelling: specific

* spelling: specify

* spelling: synchronously

* spelling: through

* spelling: timeout

* spelling: triangle

* spelling: trivial

* spelling: unusual

* spelling: then

* spelling: vertically

* spelling: visible

* spelling: visited

* spelling: voice

This is done to keep in place the workaround we have for rectangular material
where PhysicalModel skips the saveLayer call.

While the documentation for MaterialType.canvas described it as
an infinite shape. The implementation has been clipping it to the
bounding rectangle for a while. And it is already used in the wild as a
rectangular piece. So we just update the documentation to match that.

This reverts commit d9ef7df9.

0672055a changed the Material widget to
always use Paths for representing the outline.
These paths are later used for clipping and drawing a shadow.
This changed introduced a performance regression, see:
https://github.com/flutter/flutter/issues/14403

We did not expect a path that is a rounded rectangle to be less
performant than a rounded rectangle, as Skia should be able to tell the
path is just a rounded rectangle.
Until we find a solution for this regression, we keep using RRect when
we can represent the shape with it.

This triggered an analysis failure only on the devicelab.

For backward compatibility we keep supporting specifying the shape as a
combination of MaterialType and borderRadius, and we just use that as a
default when shapeBorder is null.

To cleanup the implementation if shapeBorder was not specified we just
translate the specified shape to a shapeBorder internally.
I benchmarked paint, layout and hit testing, with the specialized shape
clippers vs. the equivalent path clippers and did not see any
significant performance difference.

For testing, I extended the clippers/physicalShape matchers to match either the
specialized shape or the equivalent shape.

This widget evolved over time by multiple people, I'm just trying to explain
in a more direct way what the widget is currently doing.

This provides a way to draw colors, images, and general decorations on Material widgets, without interfering with InkWells that are further descendants of the widget.

This thus provides a cleaner way to solve the issue of FlatButtons and InkWells not working when placed over Image widgets than the old hack of introducing a transparency Material.

Fixes #3782.

Also, some fixes to documentation, and remove a redundant property on the Image widget.

This attempts to apply some of what we learnt from UX studies, namely
that people wonder how to add multiple children to widget that take
one child.