Fix DuckDuckGo HTML search
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#22090
- [x] There are tests for these changes
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Before, it would assign the name too late,
causing scripts (which will not wait for another tick)
to accidentally spawn pop-up windows instead of loading
into the iframe.
Spec: https://html.spec.whatwg.org/multipage/input.html#input-type-change
In short, this resets the selection to the start of the field when the
type has changed from one which doesn't support the selection API to one
that does.
I couldn't see an existing WPT test covering this.
Per the spec, selectionStart and selectionEnd should return the same
values regardless of the selectionDirection. (That is, selectionStart is
always less than or equal to selectionEnd; the direction then implies
which of selectionStart or selectionEnd is the cursor position.)
There was no explicit WPT test for this, so I added one.
This bug was initially quite hard to wrap my head around, and I think
part of the problem is the code in TextInput. Therefore, in the process
of fixing it I have refactored the implementation of TextInput:
* Rename selection_begin to selection_origin. This value doesn't
necessarily correspond directly to the selectionStart DOM value - in
the case of a backward selection, it corresponds to selectionEnd.
I feel that "origin" doesn't imply a specific ordering as strongly as
"begin" (or "start" for that matter) does.
* In various other cases where "begin" is used as a synonym for "start",
just use "start" for consistency.
* Implement selection_start() and selection_end() methods (and their
_offset() variants) which directly correspond to their DOM
equivalents.
* Rename other related methods to make them less wordy and more
consistent / intention-revealing.
* Add assertions to assert_ok_selection() to ensure that our assumptions
about the ordering of selection_origin and edit_point are met. This
then revealed a bug in adjust_selection_for_horizontal_change() where
the value of selection_direction was not maintained correctly (causing
a unit test failure when the new assertion failed).
