Now, we write the data recieved to a file when the user drags a file
onto the Spice Viewer window. Once complete, the FileExplorer will open
with the copied file highlighted.
The old message system was very dependent on syscalls, and the overall
structure made it hard to implement new features.
The new message system is pretty expandible, where each message has its
own dedicated class. As well as this, we now use Core::File and
AK::Stream for reading and writing messages.
Using AK::Stream also allows us to change the actual data source
(in this case, Core::File) without having to update a whole lot of code
in the future.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
A SPICE agent communicates with the host OS to provide nifty features
like clipboard sharing :^)
This patch implements only plain-text clipboard sharing.
See: github.com/freedesktop/spice-protocol/blob/master/spice/vd_agent.h
