Stable today is 193 + endcap width (16), which is also what the previous canary was -- you should be able to line up stable and previous canary and get favicons aligned with each other by offsetting a bit.  The rects on your image don't look like what the code was doing, to me.

I can match stable by returning to the previous value (which seemed pretty good to me), but 240 isn't a value very near that, and I think it probably includes endcap width (so you really wanted something like 224?).  I could try to do something more halfway between like 210 + endcap width.

Fun fact: stable Mac and stable Windows had different default widths. I guess the tab width adopted the windows model when we switched to Macviews. 

I still think the 256 (240 + 16 endcap width) is desirable. Brings more information to the tab than what other browsers are doing. 

Deleted: tabs.png 108 KB

	tabs.png 108 KB View Download

Assigning to myself until there's better confidence around a decision here.

It's really easy to change this number -- it's a one-line change I can make in minutes.  I think anything narrower than 268 is good, so why don't I at least start with 240.

In your picture in comment 2, for true equivalence, you'd want to use 193 px in the second row, not 180 -- the width of the content + what we consider the padding around it (which is half the slanted endcap width on each end), since that's what you're measuring for other browsers.

With the addition of the close-x, Peter's convinced me that having the shorter 240 is better than the 268. Assigning back with original priority. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/85c6ab8c18e2d8e282ce5fe08a1ddd86f4b1fdf5

commit 85c6ab8c18e2d8e282ce5fe08a1ddd86f4b1fdf5
Author: Peter Kasting <pkasting@chromium.org>
Date: Fri Jun 29 04:10:25 2018

Reduce default refresh tab width to 240.

Bug:  856896 
Change-Id: I5897da89ffbf38a5ca7fbce3205aefb770d81ecc
TBR: kylixrd
Reviewed-on: https://chromium-review.googlesource.com/1119646
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571380}
[modify] https://crrev.com/85c6ab8c18e2d8e282ce5fe08a1ddd86f4b1fdf5/chrome/browser/ui/views/tabs/tab.cc

Able to reproduce the issue on chrome version 69.0.3473.0(build without fix)
Verified the fix on Mac 10.12.6, Windows-10 & Ubuntu 14.04 on Chrome version #69.0.3479.0 as per the comment#0
Attaching screenshot for reference.
Observed "able to see tab strip width smaller when compare to build without fix"
Hence, the fix is working as expected.
Adding the verified label.

Thanks!

Deleted: 856896.png 224 KB

	856896.png 224 KB View Download