The goal is to split up some of the more complicated screens, like the
publish comments screen, into multiple RPCs. This is obviously a bit
more server load in the short term, but makes it much easier to convert
complicated screens piecemeal.
Because the final callback for the screen is a ScreenLoadCallback, which
needs to "own" the screen and handle displaying on success for failure,
we need to be able to specify the order in which onSuccess methods are
called.
Change-Id: Ie459fd1f91bbe10cd45a0f67a76a59e9f8890aa7
fbc3e1709e
