Like the other similar commits, we were doing the same work in all
code paths, just with a much more error-prone approach.
We can also now remove the now-unused finish_initial_narrow function.
Like the other commits in this series, we were already doing this in
all of the callers of load_messages; this centralizes that logic in a
less ad-hoc feeling way.
We no longer use or need the start_initial_narrow function.
Previously, each individual caller of load_messages that passed
num_before > 0 would do its own manual management of fetch_status;
now, we just do it inside load_messages.
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 reverts commit bcdd12773e.
We need to do some improvements in handling FetchStatus for initial
narrows before this will be safe to deploy in production.
If individual messages arrive before we get the latest
messages from the server, they can create gaps in rendering,
and would often be offscreen anyway, so we just ignore them.
Tim Abbott
Armaan Ahluwalia
Steve Howell