…ion (#43279)

fixes flutter/flutter#128709

requires flutter/flutter#129652

The issue is that when textfield focus in framework and web engine a11y are out of sync, the framework keep sending update with textfield focus = true and causes web engine to keep refocusing the textfield.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

related flutter#128709

engine PR: flutter/engine#43279

The web engine requires a way to unfocus textfield, It comes to nature
to me that we should leverage didGain/didLose a11y focus action. I also
unifies the action handler of all desktop platforms

## Pre-launch Checklist

- [ ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [ ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ ] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [ ] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

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[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
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[Flutter Style Guide]:
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…ter#129652)

…ion (flutter#43279)

fixes flutter/flutter#128709

requires flutter/flutter#129652

The issue is that when textfield focus in framework and web engine a11y are out of sync, the framework keep sending update with textfield focus = true and causes web engine to keep refocusing the textfield.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ter#129652)

…ion (flutter#43279)

fixes flutter/flutter#128709

requires flutter/flutter#129652

The issue is that when textfield focus in framework and web engine a11y are out of sync, the framework keep sending update with textfield focus = true and causes web engine to keep refocusing the textfield.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

…xtField` (#159823)

While going through `TextField` and `CupertinoTextField` I noticed
#94898 and
#129652 did not make it over to
`CupertinoTextField`. This PR brings over those changes to
`CupertinoTextField`. On Linux after this change the
`CupertinoTextField` now focuses when gaining a11y focus, and unfocuses
when losing a11y focus.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

Co-authored-by: Renzo Olivares <[email protected]>