Chrome Version: 69.0.3475.0 (Official Build) Revision 95ab095d962f25bee2255b45bc08707b683c821c-refs/branch-heads/3475@{#1} (64 Bit).

OS: Linux(14.04 LTS)

Steps to reproduce:
1. Launch chrome and navigate to chrome://settings/appearance and set 'Classic' theme.
2. Close the browser and launch the browser again. (with 1 NTP)
3. Open one more NTP, close one of the NTP and observe Tab-Strip.

Actual Result: White patches are seen while hovering on Tab-Strip.
Expected Result: White patches should not be seen.
 
This is a Non-regression issue seen from 'M69' series, build #69.0.3473.0 (Since the New UI is implemented)

Note: Issue is not seen on Mac(10.12.6,10.13.1,10.13.6,10.14), Windows(7,8,8.1,10) OS.

Kindly refer the screen-cast from below link

https://drive.google.com/drive/folders/1wq9CMcYzRbjsjy3WKHE8me4ppIpOq3SH?usp=sharing

Thank You!