8128e88474
This patch adds a new layout profiling sub-category "LAYOUT_Printing" for the
markers added here.
I'm adding an "interval"-type marker ("AUTO_PROFILER_MARKER_TEXT") for the
function-calls that seem likely to occupy measurable amounts of time (due to
touching the filesystem or printer driver), vs. single-point-in-time markers
("PROFILER_MARKER_TEXT") for functions whose duration isn't particularly long
or interesting, or whose durations we're already measuring with other
closely-associated interval-markers.
Differential Revision: https://phabricator.services.mozilla.com/D191001