Thanks for all of these! I'll do a big triage of  Issue 671916  blockers when the current phase is complete. See go/macviewstracking

spqchan@, can you take a peek at this please? :)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2234f2313c767f2c7b8e26c66d084abbe891e8c6

commit 2234f2313c767f2c7b8e26c66d084abbe891e8c6
Author: spqchan <spqchan@chromium.org>
Date: Thu Jan 18 19:26:04 2018

[Views] Fix extension button vertical alignment

The current toolbar layout assumes that all of the child
views on the toolbar, except for the location bar, have the
same height.

However, on Mac, the browser action buttons have a slightly
smaller height than the other buttons. This causes the
browser action buttons to be vertically misaligned.

This CL addresses the issue by calculating the browser action
container layout separately from the rest of the child views.

Bug:  792568 
Change-Id: I6be4c480dae8259ada79491b843aebbee5e6fcfc
Reviewed-on: https://chromium-review.googlesource.com/871572
Commit-Queue: Sarah Chan <spqchan@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530226}
[modify] https://crrev.com/2234f2313c767f2c7b8e26c66d084abbe891e8c6/chrome/browser/ui/views/toolbar/toolbar_view.cc

Verified the fix on Mac 10.13.1 using Chrome version #65.0.3325.0 as per the comment #0.
Attaching screen shot for reference.
Observed that the position of extension icon properly aligned.
Hence, the fix is working as expected. 
Adding the verified labels.

Thanks...!!

Deleted: 792568 cl verified.png 7.5 KB

	792568 cl verified.png 7.5 KB View Download

> Verified the fix on Mac 10.13.1 using Chrome version #65.0.3325.0 as per the comment #0.

This is the MacViewsBrowser version of Chrome Mac - unless you compiled 65.0.3325.0 with the proper flags you are likely using the non-MVB version which doesn't exhibit this bug?