cannot use Moat if a meek bridge is configured

If Tor Browser is configured to use a meek transport (e.g., meek-amazon or meek-azure), the Moat interface cannot be used to request bridges from BridgeDB. The root cause is that Tor Launcher's Moat implementation uses the same meek client programs and configuration as the built-in meek bridges use, which means when Moat starts up it starts an "invisible" firefox that tries to use the profile.meek-http-helper profile (which is already in use).

Ideas for fixing this (from ticket:23136#comment:55): a) Use a separate browser profile for the meek browser when it is used for Moat (this requires a fix for #12716 (moved) and possibly other things inside meek-client-torbrowser). b) Give up on using the secondary browser and use meek-client to obfs4proxy's meek_lite mode for Moat. This has the downside that the TLS fingerprint will not match Firefox's when doing Moat). c) Modify Tor Launcher to kill the tor daemon before using Moat. But this might have undesirable side effects because some other part of the browser may be using the Tor network (e.g., for a file download). Also, while Tor Launcher knows how to restart tor if it is killed, it might be difficult to make sure we kill and restart tor in a robust fashion when we are in the middle of configuring settings.

Kathy and I are currently in favor of pursuing a) but could be convinced to do something else.