I could repro. This is the autocomplete feature.

The id of the field is "search". I suppose it's the same thing for Amazon. That's why you see it there. I'll update that field so that it doesn't get autofilled.

Thanks!

https://chromium-review.googlesource.com/c/chromium/src/+/1156912 doesn't fix the issue. Still see this in the latest Canary.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1dbbefef370e1b5d32aad7105fd83c6901422b9f

commit 1dbbefef370e1b5d32aad7105fd83c6901422b9f
Author: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Date: Thu Sep 27 20:04:29 2018

Set autocomplete attribute of search field on the flags page to off.

The issue here was the autocomplete feature, not autofill.
Autocomplete is disabled when the attribute is set to off.

Bug:  869516 
Change-Id: Ib18953ed5e147cf6bab87b2c389ac75e83be13cd
Reviewed-on: https://chromium-review.googlesource.com/1249506
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594835}
[modify] https://crrev.com/1dbbefef370e1b5d32aad7105fd83c6901422b9f/components/flags_ui/resources/flags.html

You are right, what you saw was the Autocomplete feature, not the Autofill feature, I was mistaken. Setting autocomplete="off" will turn the suggestions off for that.

I've started looking at ways in which we can improve/fix the Autocomplete feature. This kind of behavior is undesirable and the feature should be revisited to get this fixed at the root.

Thanks for checking back, and let me know if you have other issue.