The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9e742fee15a89bc9c2cc8e4fdb99d2c3d9538028

commit 9e742fee15a89bc9c2cc8e4fdb99d2c3d9538028
Author: Ioana Pandele <ioanap@chromium.org>
Date: Thu Oct 11 19:07:54 2018

[Android] Hide the KA when tapping outside of page

The KA relies on the FocusedNodeChanged event that it receives as a
RenderFrameObserver. This event however is not triggered when the focus
moves outside the frame (e.g. on the omnibox). In order to detect such
a focus change we use DidEndTextFieldEditing to hide the KA, same as
for the autofill popup.
When the user taps back onto the field DidCompleteFocusChangeInFrame is
called, which leads to the accessory being shown again.

TBR for 1 line in components/autofill/content/renderer/autofill_agent.cc
TBR=dvadym@chromium.org

Bug:  893695 
Change-Id: I76a66ce43fad0a74c0abbc10c42d8916fd7e891a
Reviewed-on: https://chromium-review.googlesource.com/c/1268246
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Ioana Pandele <ioanap@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598878}
[modify] https://crrev.com/9e742fee15a89bc9c2cc8e4fdb99d2c3d9538028/chrome/renderer/autofill/password_autofill_agent_browsertest.cc
[modify] https://crrev.com/9e742fee15a89bc9c2cc8e4fdb99d2c3d9538028/components/autofill/content/renderer/autofill_agent.cc
[modify] https://crrev.com/9e742fee15a89bc9c2cc8e4fdb99d2c3d9538028/components/autofill/content/renderer/password_autofill_agent.cc
[modify] https://crrev.com/9e742fee15a89bc9c2cc8e4fdb99d2c3d9538028/components/autofill/content/renderer/password_autofill_agent.h

On second thought I'm not sure this change is a good idea. According to:

https://www.chromium.org/chromium-os/chromiumos-design-docs/disk-format

we go out of our way to make sure that we can boot on an EFI system, and though this doesn't happen on chromebooks this may happen in other situations (virtualized Chrome OS instances, early proto hardware, etc.)

Abandoning for now.