App Version: 56.0.2924.5 dev 
iOS Version: 10.1.1, 10.2 (iOS 10 only) 
Device: iPhone only 

Steps to reproduce:
 1. Perform fresh install and launch chrome 
 2. In landscape mode, run through first run slides
 3. In Sign in to Chrome screen, tap on ‘Add Account’ 
 4. Tap on ‘Close’ in Sign in screen. Again tap on ‘Add Account’ 

Observed results:
At Step 3, Sign In screen opens in landscape mode 
At Step 4, Sign In screen opens in portrait mode 

Expected results:
‘Sign In’ screen should open in landscape mode on any number of taps on ‘Add Account’ 

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 Dolphin/Safari/Firefox: Firefox: NA, Safari: NA
Bug reproducible on current stable build (App Version, iOS Version): Yes on 54.0.2840.91 
Bug reproducible on the current beta channel build (App Version, iOS Version): Yes on 55.0.2883.55, Yes on M56.0.2924.5

Link to video/image:
iOS 10
https://drive.google.com/a/google.com/file/d/0B0yKxJxj4vw1MDRqakZ6QjRkNDQ/view?usp=sharing

iOS 9
https://drive.google.com/a/google.com/file/d/0B0yKxJxj4vw1NzRyOTdMOHVDVjQ/view?usp=sharing