App Version: 71.0.3578.49 Beta
iOS Version: 10.3.3, 11.4.1, 12.0.1
Device: iPhone 8, iPhone 8 plus                                                                                                                                                                                                                                                                              

Prerequisite: 
1. Enable ‘#out-of-web-fullscreen’ flag from chrome://flags
2. Enable ‘#browser-container-fullscreen’ flag from chrome://flags

Steps to reproduce:
1. Launch chrome in portrait mode
2. Load youtube.com and load any video in fullscreen
3. Change the device orientation to landscape and then back to portrait
4. Exit from fullscreen video

Observed results:
Notice that top aligned element goes behind the top toolbar

Expected results:
Top aligned elements shouldn’t go behind the top toolbar

Number of times you were able to reproduce: 5/5
Bug reproducible after clean install: Yes
Bug reproducible after clearing cache and cookies: Yes
Bug reproducible on Chrome Mobile on Android: Not tested
Bug reproducible on Safari/Firefox: Firefox: NA, Safari: NA
Bug reproducible on current stable build (App Version, iOS Version): NA on M70 (Feature available from M71)
Bug reproducible on the current beta channel build (App Version, iOS Version): Yes on M71 Beta 

Link to Video:
https://drive.google.com/file/d/18oNELhPm7Z5G0LJZL3grxEDHs57tmwKB/view?usp=sharing