Note that I'm intentionally *not* leaving a blank line between the license
block and the "IWYU pragma" line, in nsDisplayItemTypesList.h. This matches the
prevailing style that I found in other files that have "IWYU pragma" lines.
I copied the boilerplate comment directly from the Coding Style MDN page:
https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Coding_Style#Mode_Line
MozReview-Commit-ID: ACoHkDFe8Z3
--HG--
extra : rebase_source : 374d28fea72cfb76043bde724120877b15092d01
This field will be needed for servo side alias pref handling on the
next patch.
MozReview-Commit-ID: LyH2UwZEvMy
--HG--
extra : rebase_source : f3f921581a0cdcc9c63520b528bd0f1e12568958