Motivation / Problem

_realtime_tick is a global variable that counts time, driven by the video-drivers mainloop. In many cases there is no longer a need to do it this way, as we can just use std::chrono to get the time any moment we want in our code.

Additionally, because we have std::chrono::seconds etc, there is less bla about what unit a const has, making the code slightly more readable.

Description

For the first commit

Pretty straight-forward. I did rework some functions slightly to make them simpler. Mostly, wrapping no longer happens (well, every 250+ years (REAL LIFE YEARS @ldpl , not game years!), so .. yeah .. never), so that code can be removed.
Most noticeable change would be the advertisement; instead of keeping 2 variables for "next", just keep one "last" and check if the duration elapsed.

I tested all timeouts except one.

• Admin, nc connect and don't do anything. Works.
• Client timeout, iptables drop the TCP traffic after connect. client gets dialog counting up to 15 seconds.
• Server lag timeout, harder to test, but modified the code to trigger this path.
• Chat, by typing something and waiting for the timeout,
• Advertisement, both failed and success advertisement, by letting a server do that.
• Content service, clicking the button, waiting 60 boring seconds, checking netstat -n that the connection is gone.

All works as expected.

For the second commit

Two cases were straight-forward. Double click and hover. Nothing special about it. Tested, works as expected.

The third case was a bit more odd, as it was abusing _realtime_tick to now if any draw-ticks happened. This is because every mouse interaction can cause a call to HandleMouseEvents. Luckily, we already have a counter to check if any call to that function has been done during the draw-tick, so instead of using _realtime_tick like that, use the variable that was intended for it.
To have it slightly more readable, this did mean the function had to be moved up a bit.

For the third commit

Yes, _realtime_tick was in debug.h ... seems it was originally meant for debugging :D Super weird ..

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker