We want to add a constraint googDisableLocalEcho in the audio part of getUserMedia call. It only works with audio capturing (either from the whole system or a tab). If set googDisableLocalEcho:true, then we are going to mute the local playback of the audio being shared.

For example, if one wants to share a tab, and specifies getUserMedia({video:..., audio:{mandatory:{sourceId:<some id>, googDisableLocalEcho:true}}}) Then during the sharing of the tab, the tab is muted on the sender's side. Otherwise the shared tab is still playing out on the sender's side.