Advertise Messages' immutable properties as such
Submitted by Simon McVittie
Assigned to Telepathy bugs list
Description
tp-spec 0.21.2 clarified that MessagePartSupportFlags, SupportedContentTypes and DeliveryReportingSupport are immutable.
As such, they should be in NewChannels.
Due to Bug #30949, DeliveryReportingSupport won't work reliably until we depend on telepathy-glib 0.13.3, so the tests shouldn't test its value, only that it exists (unless its value would be 0 anyway).
Version: git master