* Create 'center' template

* Implement DropdownButton.selectedItemBuilder

* Add constraints property, updated default constraints for ToggleButtons to 48x48

* Add kMinInteractiveDimension constant to ToggleButtons

Fixed passing autofocus to MaterialButton, and when rebuilding Focus widget, and added a test for Focus and MaterialButton to test that it works properly.

* Add tabOffsetEqual null check with TODO

* Added properties in DropdownFormField to match DropdownButton

* Minor style guide related changes

* Minor improvements to framework documentation.

* maybePop documentation fix

* Mark some flutter_test arguments required.

Without these set, we get a crash.

* Minor correction to ListView docs

* CupertinoTabBar

* CupertinoButton

* update

* review

This reverts commit 6ef80b44.

Docs improvement after seeing "null" showing up for TextWidthBasis.

This reverts commit e3f8d055.

* Automatic focus highlight mode for FocusManager

This re-lands the highlight mode change.

* Review Changes

* WIP

* trying out different numbers

* apply intrinsic width and height

* update

* update behavior

* documentation

* wip

* fix tests

* constants

* respect theme

* respect theme

* add new test

* add new test

* update

* review

* update golden commit hash

fix sliverfixedextent with sliverchildbuilderdelegate does not correct calculate max scroll extent (#39142)

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

Use the entire appBarTheme from the showSearch delegate for the search pages appBar theme, rather than just a select set of fields.