This came up during code review of https://chromium-review.googlesource.com/c/chromium/src/+/899954.

As we move network logic off IO thread and onto network service, we should be able to move the core logic off IO thread. In addition, we should also investigate moving parts of the DIAL / Cast MRPs that are currently running on the UI thread onto some other sequence. This means identifying remaining dependencies on UI thread (shouldn't be too many) and their replacements.

The fact that MR already talks to the MRPs via Mojo helps with the move. We can also consider servicification of MR / MRPs as part of the work. The plan is to figure out a high level plan for this work by Q1.