Please find the below per-revision bisect information:
Good Build —56.0.2917.0—431726
Bad Build ——56.0.2918.0 —431795

Bisect Tool Info:
----------------
You are probably looking for a change made after 431735 (known good), but no later than 431736 (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/fb416fc8cea1442a3eae4d81b17ea310d75a0d99..c03ac1f988225abce504a023f29db90c6dbb2872

Review-Url: https://codereview.chromium.org/2494943003

dschuyler@ Could you please take a look at this issue.

Thank you!

It looks like users are no longer able to enter a block side that doesn't have the [*.] prefix. The [*.] appears to be added automatically, which the old options did not do.

CL 2682023002

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/280885a8ab97723e5f1c4bb6f9fdb1bda1418b2a

commit 280885a8ab97723e5f1c4bb6f9fdb1bda1418b2a
Author: dschuyler <dschuyler@chromium.org>
Date: Wed Feb 08 22:35:12 2017

[MD settings] allow site exceptions without pattern wildcard

This CL removes the automatic addition of a '[*.]' prefix when entering
content site exceptions. So if the user entered 'google.com' it was
automatically being promoted to '[*.]google.com'. This CL removes that
automatic promotion/alteration of what user entered.

BUG= 685949 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2682023002
Cr-Commit-Position: refs/heads/master@{#449112}

[modify] https://crrev.com/280885a8ab97723e5f1c4bb6f9fdb1bda1418b2a/chrome/browser/resources/settings/site_settings/add_site_dialog.js
[modify] https://crrev.com/280885a8ab97723e5f1c4bb6f9fdb1bda1418b2a/chrome/browser/resources/settings/site_settings/site_settings_behavior.js

The fix makes the new settings behave the same as the old options page in this area.
(chrome://settings/contentExceptions#images)
For example: blocking wikipedia.org will not block images on the wikipedia home page because www.wikipedia.org (or [*.]wikipedia.org) is needed to block that page. This is true on the old options and the new settings now (with the CL above) match that behavior.
Example 2: if www.wikipedia.org is blocked by entering the value in options or settings and then set to allowed with the Omnibox icon (as demo'ed in this bug), the block on www.wikipedia.org will remain and an https://www.wikipedia.org:443 will be added as allowed. This happens in the old options and the new settings.