This is a regression issue broken in ‘M-65’ and using the per-revision bisect providing the bisect results,
Good build : 65.0.3299.0 (Revision : 524907)
Bad build : 65.0.3300.0 (Revision : 525555)

You are probably looking for a change made after 525476 (known good), but no later than 525477 (first known bad).

CHANGELOG URL:
https://chromium.googlesource.com/chromium/src/+log/ef62139da55ec66c148556896ca3bf0b23b886a0..c6dd96ffb49cea709f1373d01e7e7e19307a886f

Suspect : https://chromium.googlesource.com/chromium/src/+/c6dd96ffb49cea709f1373d01e7e7e19307a886f

@sdy : Could you please look into the issue, pardon me if it has nothing to do with your changes and if possible please assign it to concern owner.

Note : This is Mac OS specific issue and the same is not observed on Windows(7,8,10) and Linux(14.04 LTS) OS.

 Issue 797319  has been merged into this issue.

Working on this now. Adding RBS from the issue I just merged.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f57b9e14a1145268314b297e80f38c529f94535a

commit f57b9e14a1145268314b297e80f38c529f94535a
Author: Sidney San Martín <sdy@chromium.org>
Date: Tue Jan 02 19:53:39 2018

Add insetInView when calculating a width for a BookmarkButtonCell.

This fixes some short bookmark button titles getting truncated.

Bug:  796836 
Change-Id: I7bf68b5b5ccc7d48923da231feccb97f9c0caa34
Reviewed-on: https://chromium-review.googlesource.com/845821
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Sidney San Martín <sdy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526520}
[modify] https://crrev.com/f57b9e14a1145268314b297e80f38c529f94535a/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm
[modify] https://crrev.com/f57b9e14a1145268314b297e80f38c529f94535a/chrome/browser/ui/cocoa/bookmarks/bookmark_button_cell.mm
[modify] https://crrev.com/f57b9e14a1145268314b297e80f38c529f94535a/chrome/browser/ui/cocoa/gradient_button_cell.h
[modify] https://crrev.com/f57b9e14a1145268314b297e80f38c529f94535a/chrome/browser/ui/cocoa/gradient_button_cell.mm

This should be fixed in tomorrow's canary.

Hey sdy@, Happy New Year and thanks for fixing this issue. I checked it in latest Snapshot 526532 and unfortunately the padding on the right side is no longer correct. It has 2pt too much padding now on the right side and the single favicon or favicon_with_text are no longer centered on the button. It should be 4pt too on the right side again.

Attached are screenshots. Could you please take a look at this issue again?

Thanks!
Mehmet
 

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	2pt_too_much_padding_favicon_only.png 19.3 KB View Download

Deleted: 2pt_too_much_padding_favicon_with_text.png 19.9 KB

	2pt_too_much_padding_favicon_with_text.png 19.9 KB View Download

Additional notes to my comment 6:

- I also noticed, that the spacing between the bookmarks has also been changed and has more padding than before. A screenshot is attached.

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	spacing_between_bookmarks.png 46.0 KB View Download

mehmet@: Thanks for catching this. I'm working on a fix.

Reopening per c#6.

Change is up for review:
https://chromium-review.googlesource.com/c/chromium/src/+/848032

Update : 
Retested the above issue on Mac(10.12.6), (10.13.1) & (10.13.3) OS using latest Canary #65.0.3310.0 and issue is fixed. Now, complete name is seen for 'Apps' instead of continuation. Kindly review an attached screen-cast.

Thank you!

Deleted: Current_Result.mov 663 KB

Current_Result.mov 663 KB Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/84077a2b7d10b90f92cc43df232723cbbf46880a

commit 84077a2b7d10b90f92cc43df232723cbbf46880a
Author: Sidney San Martín <sdy@chromium.org>
Date: Wed Jan 03 18:09:45 2018

Fix a regression that made bookmark buttons too wide.

r526520 started including a bookmark button's inset when calculating its width.
This turns out to change the layout and, because the inset is cr_lineWidth,
there's no way to pick padding constants which make the padding and spacing the
same on retina and non-retina.

The inset (which comes from GradientButton) isn't really used in MD, so
overriding insetInView: to return zero gets the right behavior back. This
class's layout code could still use cleanup.

Bug:  796836 
Change-Id: I52741d9fb92db92fa07ba8b27077d8451383a47f
Reviewed-on: https://chromium-review.googlesource.com/848032
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Sidney San Martín <sdy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526739}
[modify] https://crrev.com/84077a2b7d10b90f92cc43df232723cbbf46880a/chrome/browser/ui/cocoa/bookmarks/bookmark_button_cell.mm

mehmet@, let me know if this change fixed the spacing issue you found.

Update : 
Verified this issue on Mac(10.12.6), (10.13.1) & (10.13.3) OS with latest Canary build #65.0.3311.0 and the issue is no longer reproducible. The fix is working as intended. Kindly review an attached screen-cast.

Thank you!

Deleted: Latest_Results.mov 2.1 MB

Latest_Results.mov 2.1 MB Download

Nice, thank you for checking!

> mehmet@, let me know if this change fixed the spacing issue you found.

Thank you sdy@. Spacing and padding is looking fine again :-)

Just only one thing I noticed, but I think we can live with it is, that depending on the length and the letters when the bookmark name is elided, the padding on the right side is sometimes smaller or larger. It should also always be the same padding like on the left side. Please find attached a screencast. Please let me know, if I should file a separate report for this issue or if you think we can leave it as it is.

Thanks :-)

+ screencast

Deleted: elided_bookmarkname_padding_right.mov 1.6 MB

elided_bookmarkname_padding_right.mov 1.6 MB Download

Oh, interesting. Please do file a bug — I'm guessing that it's always been like that, but it would be good to fix either way.

--> Done:  issue 799096