Add the option to configure a chip check mark color

This changes the behavior of text fields, Material buttons, and Chips so that if they are disabled they lose focus. Before this change, it was possible to disable a control and then use focus traversal to reach it anyhow, and in the case of text fields, enter text into a disabled field.

Fixes #33985

* Chip keeps track of state, resolves text color

* Add horizontal padding and properly constrain chip label calculations

* Added regression test for avatar, label and delete icon constraint

* fix indentof statements in BlockFunctionBody

* fix indentof statements in BlockFunctionBody in tests

* 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

[Material] Add ability to set shadow color and selected shadow color for chips and for chip themes (#28163)

* Add ability to set shadow color for chips and for chip themes

* Add selected shadow color as a property as well

* Update phrasing of documentation

* Address PR feedback

Allow the theme to provide these values to Chips

Expose elevation on chips and allow for it to be customized by the developer.

Adds avatarBorder property to SelectableChipAttributes and uses the outer path to draw the darkened layer.

* Future<void> main

* Future<void>.delayed

* prefer_void_to_Null

* address review comments

* prefer_void_to_null in flutter_test

* fix CI

* choice chip fix

* added test

* Make Chip press elevation customizable.

* Refactor of cupertino/material/widgets app

* update docs 

* Update tests for const

This reverts commit 61cf946b.

* Make CupertinoApp and MaterialApp both use WidgetsApp for Navigator

* Make CupertinoApp and MaterialApp const constructors

* Make WidgetsApp routes aware

* Update tests

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

This fixes https://github.com/flutter/flutter/issues/20746

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.

This reverts commit 989f5741.

This optimizes the AnimatedSwitcher so that it tags the right widget with its keyed subtree, and avoids rebuilding the transition unnecessarily.

This significantly improves the performance of Chips (which uses AnimatedSwitcher to swap out it's avatar and delete icon children).

This converts the chips to use a ChipThemeData to get most of their customization values from (if not overridden by specific arguments to the chip constructors), and to have the base ThemeData contain one of these. It also adds the ChipTheme widget that will allow overriding the theme for a particular subtree in the widget hierarchy.

Added tests for both, and just more tests in general for the Chips.

There was a bug in the size calculation for the height of the chip label, where it would force the label to be larger than it wanted to be, causing text to not be vertically centered.

This renames the chip's border attribute to 'shape' so that it is consistent with the other places where we supply a ShapeBorder.

This is a breaking change, but a very small one: the border attribute was introduced only a few months ago, and is not widely used.