1135055 - [Youtube][HTML5] "Default view"/"Theater mode" works incorrectly after using Next/Previous from Full screen

Status: NEW

(Core :: Audio/Video: Playback, defect)

Description

[[SV Manager] Florin Mezei, QA (:FlorinMezei)]

Reproducible with: 
- Firefox 36 RC - BuildID: 20150219174507
- latest Firefox 37 Aurora - BuildID: 20150220004124
- latest Firefox 38 Nightly - BuildID: 20150219070749

Reproducible on: Mac OS X 10.9.5 (Retina), Windows 7 x64, Windows 8.1 x86

NOT reproducible on: Ubuntu 14.04 x64

Steps to reproduce:
1. Open Firefox and go to https://www.youtube.com/html5 and click "Request the HTML5 player".
2. Open a list o videos e.g. https://www.youtube.com/watch?v=y6Sxv-sUYtM&list=RDy6Sxv-sUYtM#t=1.
3. Enter full screen.
4. Click Next to start the next song.
5. Click on "Default view"/"Theater mode" while still in full screen.

Expected results:
Player exits HTML5 full screen mode and displays mode selected at step 5.

Actual results:
Player exits HTML5 full screen mode but displays opposite mode from the one selected at step 5 ("Theater mode" if "Default view" was clicked, and vice-versa).

Notes:
- the issue does not show if step 4 is skipped
- this is not a recent regression as the issue also reproduces in Firefox 32.0.3