Using the per-revision bisect providing the bisect results,
Good build: 57.0.2958.0 (Revision : 439976)
Bad build: 57.0.2959.0 (Revision : 440307)

You are probably looking for a change made after 440062 (known good), but no later than 440063 (first known bad).

CHANGELOG URL:

The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  https://chromium.googlesource.com/chromium/src/+log/a4fad38f7761ee4193d30b80416d26c6412b991c..40ccb2581137efc2fc7d2a1041073fa00caed75a

From the CL above, assigning the issue to the concern owner 

@tkent - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Review-Url: https://codereview.chromium.org/2586143004

Thanks!

Minimum repro:

data:text/html;charset=utf-8,<a href="http://www.gogole.com/" onfocus="this.href='https://www.google.com'">Google</a>

1. Open the above URL
2. Press TAB to focus the link.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ef80b9a60d5b8809711ab18632705e09fe64e3c6

commit ef80b9a60d5b8809711ab18632705e09fe64e3c6
Author: tkent <tkent@chromium.org>
Date: Wed Jan 11 10:28:34 2017

Updating href attribute should not blur.

In HTMLAnchorElement::attributeChanged,

    params.name != hrefAttr && isLink()

should have been

    params.name != hrefAttr || isLink()

This CL fixes it, and improves code readability.

BUG= 679669 

Review-Url: https://codereview.chromium.org/2623163002
Cr-Commit-Position: refs/heads/master@{#442855}

[delete] https://crrev.com/cb36c4939dda375f028ae61a6817e10d7de39161/third_party/WebKit/LayoutTests/fast/dom/HTMLAnchorElement/remove-href-from-focused-anchor.html
[rename] https://crrev.com/ef80b9a60d5b8809711ab18632705e09fe64e3c6/third_party/WebKit/LayoutTests/fast/dom/HTMLAnchorElement/update-href-of-focused-anchor-expected.txt
[add] https://crrev.com/ef80b9a60d5b8809711ab18632705e09fe64e3c6/third_party/WebKit/LayoutTests/fast/dom/HTMLAnchorElement/update-href-of-focused-anchor.html
[modify] https://crrev.com/ef80b9a60d5b8809711ab18632705e09fe64e3c6/third_party/WebKit/Source/core/html/HTMLAnchorElement.cpp