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 440297 (known good), but no later than 440298 (first known bad).
CHANGELOG URL:
  https://chromium.googlesource.com/chromium/src/+log/41b288d33cad4776bc5f09ee435703a214449aaf..172e00cdced29d37051bd7fc8faaeedb7416653c

@meacer -- 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.
Adding RB Label as this is a recent Regression. Please remove if not required.

Thank You.

+ellyjones who added the tooltip at https://codereview.chromium.org/2407853002

The tooltips aren't consistent between Win/Linux and Mac (Win/Mac only says "View site information"). Was this intentional? Do we want to do the same on all platforms?

> Win/Mac only says "View site information" 

Err, Win/Linux

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1a2fcc1a4c4a40629e10b1a067004ace091ef341

commit 1a2fcc1a4c4a40629e10b1a067004ace091ef341
Author: meacer <meacer@chromium.org>
Date: Tue Feb 14 22:00:10 2017

Display a simple tooltip text for empty labels in verbose states

As of M57, verbose state bubbles are used to display extension names.
When the process for an extension crashes or is killed, the bubble label will
be empty. This leads to a leading dot to be displayed in the bubble tooltip.
This CL fixes that.

BUG= 691922 

Review-Url: https://codereview.chromium.org/2697903002
Cr-Commit-Position: refs/heads/master@{#450484}

[modify] https://crrev.com/1a2fcc1a4c4a40629e10b1a067004ace091ef341/chrome/browser/ui/cocoa/location_bar/security_state_bubble_decoration.mm

Rechecked this issue on canary version 58.0.3013.0 on MAC 10.12.2 and fix is working as intended. No "." is displayed in the tool tip. Attached screenshot for the same. Adding TE Verified labels.

Can this fix be merged to M57 as issue is tagged with labels M57 and Stable blocker.

Deleted: Tool tip.png 31.3 KB

	Tool tip.png 31.3 KB View Download

Closing as fixed. I filed  bug 692683  to do something similar on other platforms.

Your change meets the bar and is auto-approved for M57. Please go ahead and merge the CL to branch 2987 manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), ketakid@(cros), govind@(desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1174093e0197a1ec4cb655d8ec599c6b2c0ceae7

commit 1174093e0197a1ec4cb655d8ec599c6b2c0ceae7
Author: Mustafa Acer <meacer@chromium.org>
Date: Wed Feb 15 22:25:45 2017

[Merge M57] Display a simple tooltip text for empty labels in verbose states

As of M57, verbose state bubbles are used to display extension names.
When the process for an extension crashes or is killed, the bubble label will
be empty. This leads to a leading dot to be displayed in the bubble tooltip.
This CL fixes that.

BUG= 691922 
TBR=rsesek@chromium.org

Review-Url: https://codereview.chromium.org/2697903002
Cr-Commit-Position: refs/heads/master@{#450484}
(cherry picked from commit 1a2fcc1a4c4a40629e10b1a067004ace091ef341)

Review-Url: https://codereview.chromium.org/2695303003 .
Cr-Commit-Position: refs/branch-heads/2987@{#532}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[modify] https://crrev.com/1174093e0197a1ec4cb655d8ec599c6b2c0ceae7/chrome/browser/ui/cocoa/location_bar/security_state_bubble_decoration.mm

Rechecked this issue on chrome version 57.0.2987.74 on MAC 10.12.3 and merge is working as intended. No "." is displayed in the tool tip.

Adding TE Verified labels.