DO NOT MERGE Revert video calling CLs

Reverting recent all changes relating to video calling in one CL.
This was done in i-release already, just making i-dev match the
prebuilt that was dropped in oc-dev.

*** Original CLs ***
"Use generic video icon for tachyon calls" ag/2124911
"Add alternative video call to QC action" ag/2108263
"Add experiments for video call in AOSP." ag/2065958

Test: Build app

Change-Id: I1f1eff7b1cd3a7051ae3304aef5eeab63e79e007