Revert "Reland "Do not reveal username value till user gesture.""

This reverts commit 3d4d84928567f74d93d951932eafa1b3d779923b.

Reason for revert: ASan failed interactive_ui_tests with a PasswordManagerBrowserTestBase.UsernameChanged failure.
A connection seems likely. Could you please check that?
Build: https://uberchromegw.corp.google.com/i/chromium.memory/builders/Linux%20ASan%20Tests%20%28sandboxed%29/builds/42632

Original change's description:
> Reland "Do not reveal username value till user gesture."
> 
> Original change's description:
> > Passwords are not available for a page till user gesture.
> > But for usernames it was not implemented. This patch implements
> > this: use SetSuggestedValue for username and register
> > username_element to gatekeeper, which manages revealing
> > the input suggested value to JS after user action.
> >
> > Along the way, a small improvement was implemented, setting
> > the username value only in one place which simplifies the code.
> 
> > Bug: 798492
> > Change-Id: Ib37637dd861f44b94674c6d0060ebc91dfd73cff
> > Reviewed-on: https://chromium-review.googlesource.com/850394
> > Commit-Queue: Vadym Doroshenko <dvadym@chromium.org>
> > Reviewed-by: Dominic Battré <battre@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#527598}
> 
> Original Patch is PatchSet 1.
> Flakiness was fixed on CL https://chromium-review.googlesource.com/c/chromium/src/+/859960
> This CL differs from original only in small compilation fix in PatchSet 5 (compilation
> errors were because of changes in another CL).
> 
> TBR=battre@chromium.org
> 
> Bug: 798492
> Change-Id: Ife2f67ca2cd75372ef388d077acb9d53b47be92d
> Reviewed-on: https://chromium-review.googlesource.com/854173
> Commit-Queue: Vadym Doroshenko <dvadym@chromium.org>
> Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#528593}

TBR=dvadym@chromium.org

Change-Id: I081c713b5fe18b3d01d996eee4167000ef0bb906
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 798492
Reviewed-on: https://chromium-review.googlesource.com/860381
Reviewed-by: Friedrich Horschig <fhorschig@chromium.org>
Commit-Queue: Friedrich Horschig <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528615}
5 files changed