Fenix: [Bug] fenix bottom bar covers up Reddit "open in browser" button, when opened in custom tab

[dholbert]

Steps to reproduce

1. Make fenix be the system webview for other apps to use for web content (I forget how I did this - maybe it's just making it the default browser?)
2. Open the Twitter Android app and view a tweet with a link to a Reddit post. E.g.
   https://twitter.com/rabimba/status/1206192610177511424?s=19
3. Tap the Reddit link to open in-twitter-app Fenix webview.
4. Look at the buttons at the bottom of the Reddit page.

Expected behavior

The "See this post in... Browser" button should be visible.

Actual behavior

The button is covered by the URL bar.

Device information

• Android device: Pixel 3
• Fenix version: 3.0.0 (Build #13431956)
  📦: 24.0.0, 968f858c1
  🦎: 71.0-20191125115111

This only affects the in-another-app webview experience. If I perform the STR entirely in Fenix itself (using the Twitter website instead of Twitter app), then I get expected results.

[dholbert]

Screenshot of Actual Behavior (the bug):

[dholbert]

Screenshot of expected results (when performing STR entirely in Fenix with Twitter website instead of app):

[dholbert]

Another simpler affected site (not Reddit): https://heximal-clock.glitch.me/

When loaded from the Twitter Android app via e.g. this tweet, the numeric time at the bottom gets covered by the Fenix custom-tab location bar:
https://twitter.com/tabatkins/status/1209969194843828224?s=19

Screenshot:

[mcarare]

This should have been fixed by https://github.com/mozilla-mobile/fenix/commit/686facffc6ca21c1c38765306507f2269f5314b5.
QA, can you please check? TY!

[abodea]

Verified as fixed on the latest version of Nightly from 1/7 using Samsung Galaxy S10+(Android 9).

Note that I tried with both websites(with the twitter app): reddit and /heximal-clock.glitch.me/ following the same scenario from the description.
Also, note that I verified this issue on Fenix Private-Browsing Custom Page and it worked as expected, the bottom was displayed correctly.

Based on my comment I will close this issue.