This commit prepares the frontend code to be consumed by webpack.
It is a hack: In theory, modules should be declaring and importing the
modules they depend on and the globals they expose directly.
However, that requires significant per-module work, which we don't
really want to block moving our toolchain to webpack on.
So we expose the modules by setting window.varName = varName; as
needed in the js files.
This makes sure that CSRF token is available while initializing
Socket, irrespective of the order of execution of deferred callbacks
after document becomes ready.
This is part of #9416.
We now isolate the code to transmit messages into transmit.js.
It is stable code that most folks doing UI work in compose.js don't
care about the details of, so it's just clutter there. Also, we may
soon have other widgets than the compose box that send messages.
This change mostly preserves test coverage, although in some cases
we stub at a higher level for the compose path (this is a good thing).
Extracting out transmit.js allows us to lock down 100% coverage on that
file.
Armaan Ahluwalia
Shubham Dhama
Steve Howell
Tim Abbott