Issue 13238: on iOS, force an orientation change when the current orientation is not allowed

[josh-ksr]

Fixes the iOS - Part of this issue: flutter/flutter#13238

on iOS, force an orientation change when setPreferredOrientations is called and the current orientation is not in the new list of preferred orientations

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[josh-ksr]

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[gaaclarke]

I don't see anything wrong with the code per-say. It is using KVO to bypass the Apple's API, and there are at least some reports that this hack doesn't work in some situations. @xster proposed that this functionality should be behind a new method SystemChrome.forceOrientation(DeviceOrientation orientation). (flutter/flutter#13238 (comment))

I'd like to test this on device this afternoon and hear back from @xsterbefore I give it the thumbs up.

[gaaclarke]

I've tested on device and LGTM. At a minimum please add the docstring to the test or make the selector better named. I say we look past the gap in Apple's API for now and bring in this change.

[josh-ksr]

I don't see anything wrong with the code per-say. It is using KVO to bypass the Apple's API, and there are at least some reports that this hack doesn't work in some situations.

@gaaclarke As far as I know, the case when it doesn't work is iPad with multitasking enabled, and in that case it´s not allowed/possible at all to force a specific orientation. I added some documentation about this behavior in another pull request (flutter/flutter#40743)

[gaaclarke]

@josh-ksr I think you'll have to merge master in order to fix the build_and_test_linux_unopt_debug test. The API changed a bit and your PR doesn't have those changes.

[josh-ksr]

@gaaclarke done, no more failing tests now

[chinmaygarde]

This is causing LUCI failures.