Filed this issue from Buganizer - b/75334974

Tested the issue in Android and able to observe a white line when all the tabs are closed. 

Steps Followed:
1. Launch Chrome.
2. Close all the tabs.
3. Observed that in the Zeroth tab a white bar is displayed above device navigation bar.

Chrome versions tested:
66.0.3359.30(Beta), 67.0.3374.0(Canary)

OS:
Android 8

Android Devices:
Pixel 2 XL

Using the per-revision bisect providing the bisect results,
Good Build - 66.0.3335.0 (533164)
Bad Build - 66.0.3336.0 (533409) 

You are looking for a change made after 533392(GOOD), but before 533393(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/+/61b733df8d7e9d89527cfcde4cc2207bf21d2c48

From the CL above, assigning the issue to the owner concerned.

@twellington:  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 owner concerned.

Thanks!