Add Firefox versions for api.RTCSessionDescription.toJSON (#12898)
Add Firefox versions for api.RTCSessionDescription.toJSON (#12898)

https://hg.mozilla.org/mozilla-central/rev/4f60fe3eefc58a9eda9071a66d8800cec7a59aba
chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data