The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ec715f48a366cbcf258cfa0b770b913cc1280290

commit ec715f48a366cbcf258cfa0b770b913cc1280290
Author: Parastoo Geranmayeh <parastoog@google.com>
Date: Wed Aug 08 03:25:49 2018

[Autofill] Don't overwrite user input for select.

When autofilling a select field, check if the user has previously
changed the field. If so, don't overwrite.
Note: If the user hovers over the fields, but doesn't choose any,
we should overwrite.

Bug: 868576
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: If4f9efa9bdc057e04295984a386b2083eb13a82d
Reviewed-on: https://chromium-review.googlesource.com/1158712
Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Commit-Queue: Parastoo Geranmayeh <parastoog@google.com>
Cr-Commit-Position: refs/heads/master@{#581460}
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/chrome/browser/autofill/autofill_interactive_uitest.cc
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/chrome/renderer/autofill/form_autofill_browsertest.cc
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/components/autofill/content/renderer/form_autofill_util.cc
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/third_party/blink/renderer/core/exported/web_form_control_element.cc
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/third_party/blink/renderer/core/html/forms/html_form_control_element_with_state.h
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/third_party/blink/renderer/core/html/forms/html_select_element.cc
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/third_party/blink/renderer/core/html/forms/html_select_element.h
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/third_party/blink/renderer/core/html/forms/text_control_element.cc
[modify] https://crrev.com/ec715f48a366cbcf258cfa0b770b913cc1280290/third_party/blink/renderer/core/html/forms/text_control_element.h

mahmadi@: maybe we should check this for iOS as well. Thanks.