Remove unused param
Wait for initial stylesheet load to complete

Instead of measuring on each stylesheet load at startup,
wait for the initial load of all the stylesheets to complete
and then do the necessary measurments.
Refresh scrollbars when no stylesheet is specified
Set initialLoadComplete to true in specs
:lipstick: Add ?
Merge pull request #3519 from atom/ks-remeasure-after-themes-load

Wait for themes to load before measuring