This reverts commit f0794917.

* reland add new enum change (#44281)

This reverts commit ed82bb82.

* Add opaque to barriers
* Detect opaque and test

This adds support for the fn key on macOS. It adds it to the key mappings as a supplemental mapping that overwrites the one from the Chrome headers, since the chrome headers have a TODO, but no implementation of the key.

Also, ignore the fn key entirely on macOS. This is because On macOS laptop keyboards, the fn key is used to generate home/end and f1-f12, but it ALSO generates a separate down/up event for the fn key itself. Other platforms hide the fn key, and just produce the key that it is combined with, so to keep it possible to write cross platform code that looks at which keys are pressed, the fn key is ignored.

* Adding subtitle to expansion_tile

As it stands, dropdowns currently do not focus the item that is selected, so if you select something on a dropdown, and then close it, and re-open it, then the new item is not auto-focused. This PR changes that so that selected value is focused by default when the dropdown is re-opened.

Currently, we listen to keyboard events to find out which keys should be represented in RawKeyboard.instance.keysPressed, but that's not sufficient to represent the physical state of the keys, since modifier keys could have been pressed when the overall app did not have keyboard focus (especially on desktop platforms).

This PR synchronizes the list of modifier keys in keysPressed with the modifier key flags that are present in the raw key event so that they can be relied upon to represent the current state of the keyboard. When synchronizing these states, we don't send any new key events, since they didn't happen when the app had keyboard focus, but if you ask "is this key down", we'll give the right answer

* added new lfecycle state

* update

* update

Adds the CupertinoContextMenu widget for iOS 13 support.

Fixes #42049.

* Adjust and refactor all FlatButton tests into its respective file

SliverAppBar - Configurable overscroll stretch with callback feature & FlexibleSpaceBar support (#42250)

* Adding handling of TextInputClient.onConnectionClosed messages handling to Framework

* Adding more test cases for closing connection to editable_text_test

* fixing analyze error.

* Fixing analyze error in the test file

* Fixing comments on the new method

* Adding more closing connection examples.

* Indentation change

* Remove auto-add white space

* Changing the oncloseconnection behaviour to stop editing. Updating the tests

* Addressing PR comments. Added explicit log for method channnels to the tests. Added comments to the interfaces.

* add more documentation

* Wire enableFeedback parameter through MaterialButton, RawMaterialButton, and IconButton.
Co-Authored-By: Shi-Hao Hong <shihaohong@google.com>

This is being done to match the Material spec. It will likely break many visual diff tests.

This adds accessors for WidgetsBinding.instance.focusManager and WidgetsBinding.instance.focusManager.primaryFocus so that they can be more easily found in IDEs and accessed.

This adds a top level getter for WidgetsBinding.instance.focusManager.primaryFocus called primaryFocus, and a static accessor FocusManager.instance that returns WidgetsBinding.instance.focusManager.

Makes sure that disabled InkWell/InkResponse and widgets that use them don't allow themselves to be focused.

ListTile, PopupMenu, and Stepper were not setting canRequestFocus properly on the InkWell, and InkWell was allowing focus even if it was disabled (it was basically just relying on the containing widget to set canRequestFocus properly). Now InkWell must both be enabled (have an onTap or similar) and have canRequestFocus set to true.