Chrome Version: 67.0.3396.40 (Official Build) (64-bit) Revision	4d4e946fc6b643fe97197ead24e3a6f414385ad3-refs/branch-heads/3396@{#527}
OS: Mac(10.12.6, 10.13.1, 10.13.5)

Pre-condition: Mozilla Firefox must be launched.

What steps will reproduce the problem?
(1) Launch Chrome and navigate to chrome://settings/importData
(2) Select 'Mozilla Firefox' option from drop-down list and click on 'Import' button.
(3) Now continuously multiple times click on ‘Try Again’ button on ‘Close Firefox’ dialog and observe.

Actual Result: Weird flickering is seen on tab-strip bar.
Expected Result: No such flickering should seen on tab-strip bar.

This is a Mac regression issue broken in ‘M-64’ series, below is manual regression range.

Good build: 64.0.3260.0(Revision: 514067)
Bad build: 64.0.3261.0(Revision: 514329)

Providing the bisect using per-revision bisect:

You are probably looking for a change made after 514116 (known good), but no later than 514117 (first known bad).

CHANGE-LOG 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/04f1082efb63369e19ace6dde8b62c8702303b88..6b6e8fe1fcf17e0545c688d1bfda16d6f79fd97e

Suspect: https://chromium.googlesource.com/chromium/src/+/6b6e8fe1fcf17e0545c688d1bfda16d6f79fd97e

@tapted: 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.

NOTE: 
1. This issue is also reproducible on M-66 Stable(build # 66.0.3359.139) and M-68 Canary(build #68.0.3425.0).
2. This issue is not reproducible on Win(7,8,8.1,10) and Linux (14.04 LTS) machines.

Kindly review the attached screen-cast for reference.

Thank You!
 

Deleted: Actual behavior.mov 3.5 MB

	Actual behavior.mov 3.5 MB View Download

Deleted: Expected behavior.mov 3.6 MB

	Expected behavior.mov 3.6 MB View Download