www/chromium: attempt to make it work with Microsoft Teams

• add dependency virtual_oss so the microphone works [1]
• skip assertion in h264_decoder, we will force it to initialize later [2]

PR: 246214 [1]
PR: 255484 [2]
MFH: 2021Q2
(cherry picked from commit 74647995deae7050b6f9a3bf3b3a3ef8ff25ad63)