scale compatibility with hms class

[alistaire47]

As hms has officially become part of the tidyverse, could we get a scale_x_time (and similar) so it can be plotted directly instead of hacking it through POSIXct?

For example, right now

ggplot(data.frame(time = hms::as.hms('11:11:11'), y = 1), aes(time, y)) + geom_point()

warns

Don't know how to automatically pick scale for object of type hms/difftime. Defaulting to continuous.

but plots

chron::times similarly defaults to continuous, albeit with different numbers (due to the way the data is stored, I assume). While both can be hacked through as datetimes or relabeled, the advent of hms seems to indicate the time has come for a proper set of scale_*_time functions.