Revert "Update last interacted form when JS modifies a field's value"

This reverts commit 05c6be3dfec78f091d537673fbf65605f7a41776.

Reason for revert: Speedometer2 regressions. I will reupload another CL
that tries to achieve the same result with possibly no regressions

Original change's description:
> Update last interacted form when JS modifies a field's value
>
> Autofill is currently working on replacing the observer it uses for
> disappearing elements by a direct blink connection notifying of removals
> and hiding of elements.
>
> Some notification about hidden elements are provided to Autofill during
> style recalc (e.g. changing visibility attribute to 'hidden') and during
> this Autofill is not allowed to query the focusability of a node.
>
> This causes a problem for Autofill: When submission is inferred,
> Autofill tries to extract the form of the element it was tracking, and
> part of this is querying the focusability of fields. Which means that
> if submission is inferred from a notification sent during style recalc,
> Autofill is not allowed to extract a form at submission time.
>
> The alternative is to use the provisionally saved form, which is a form
> that Autofill updates on autofill operations and user edits. In this
> context, form means either an HTML <form> tagged section or the
> collection of all unowned control elements.
>
> This CL tries to make the provisionally saved form approach the state of
> the extracted form at submission time (should we have extracted it)
> by also updating it on JS changes. To achieve that, we modify the signal
> JavaScriptModifiedAutofilledValue to JavaScriptModifiedValue.
>
> Note that this update is only performed if JS modifies the form that is
> already tracked by autofill. Which means that only user edits and
> autofill (also user triggered) have permission to change the form
> tracked by autofill from one form to another, but JS only has permission
> to update the currently tracked form.
>
> The CL also adds logic to default to the provisionally save form
> unconditionally at submission time instead of extraction.
>
> All behavior changes are gated behind a feature flag.
>
> Bug: 1483242
> Change-Id: I34635ddbe88dc49aeb31e23f2999e7bca95952bb
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5238376
> Reviewed-by: Dominic Battre <battre@chromium.org>
> Reviewed-by: Christoph Schwering <schwering@google.com>
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Commit-Queue: Jihad Hanna <jihadghanna@google.com>
> Cr-Commit-Position: refs/heads/main@{#1257853}

(cherry picked from commit 0cdb5e55e108d9287ed0aeb5a5e2bfe17566114b)

Bug: 1483242
Change-Id: Ia641dfeb7d22cf8ec89804876febe6bb1a256f24
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5310179
Reviewed-by: Mason Freed <masonf@chromium.org>
Reviewed-by: Dominic Battre <battre@chromium.org>
Reviewed-by: Christoph Schwering <schwering@google.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Jihad Hanna <jihadghanna@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1264454}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5344511
Auto-Submit: Jihad Hanna <jihadghanna@google.com>
Commit-Queue: Mike West <mkwst@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/branch-heads/6312@{#391}
Cr-Branched-From: 6711dcdae48edaf98cbc6964f90fac85b7d9986e-refs/heads/main@{#1262506}

• components/autofill/content/renderer/autofill_agent.cc[diff]
• components/autofill/content/renderer/autofill_agent.h[diff]
• components/autofill/content/renderer/autofill_agent_browsertest.cc[diff]
• third_party/blink/public/web/web_autofill_client.h[diff]
• third_party/blink/renderer/core/html/forms/html_input_element.cc[diff]
• third_party/blink/renderer/core/html/forms/html_select_element.cc[diff]
• third_party/blink/renderer/core/html/forms/html_select_list_element.cc[diff]
• third_party/blink/renderer/core/html/forms/html_text_area_element.cc[diff]
• third_party/blink/renderer/core/page/chrome_client.h[diff]
• third_party/blink/renderer/core/page/chrome_client_impl.cc[diff]
• third_party/blink/renderer/core/page/chrome_client_impl.h[diff]
• third_party/blink/renderer/core/page/chrome_client_impl_test.cc[diff]