Chrome Version:73.0.3629.0 (Official Build) Revision e65f720d1d3d9b1817d178fcabcfd2bf54f2061c-refs/branch-heads/3629@{#1}(32/64-bit)
OS : Mac(10.13.6, 10.13.1, 10.14.2)

Test URL:https://chrome.google.com/webstore/detail/cincinnati-bengals-theme/bicooooienfjkfeendjioilgefccaacb?utm_source=chrome-ntp-icon

Steps to reproduce:
1. Launch chrome ,Navigate to above URL and apply theme on browser.
2. Open Cast from wrench menu and observe Tab strip area.

Actual Result: Theme is not seen uniformly (..for Upper RHS Tab strip)on browser when cast overlay is open.
Expected Result: Theme should be uniformly seen on browser when cast overlay is open. 

This is a regression issue broken in M-70 and below is the bisect information:
Good Build : 70.0.3503.0 (Revision : 578160)
Bad Build : 70.0.3504.0 (Revision : 578510)

You are probably looking for a change made after 578333 (known good), but no later than 578334 (first known bad).
CHANGELOG 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/bcb7db78edc13f57577f0a9562c98918bdcc10ae..67d21d10815fe6d87d1785a65a50fbc386e6605b

Suspecting: https://chromium.googlesource.com/chromium/src/+/67d21d10815fe6d87d1785a65a50fbc386e6605b

@ellyjones: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.	

Kindly refer the attached screencast from below drive link:
https://drive.google.com/open?id=1z0F3M-kVTSNV97nQy_J_kep2FXt7-fRr
Thank You!