Based on FranklinDM's follow-up for the issue.
This would require browser FE changes, particularly removing the associated
code in `tabbrowser.xml`, however, that was already done in Pale Moon previously.
Other front-end applications may need to take note, though.
Based on changes from the following bugs:
* Bug 696398 - Need an api to analyze panning performance
* Bug 800031 - Include paint time in tab switch telemetry
* Bug 820167 - Enable performance measurement of tab animation
* Bug 826383 - Improve Start/Stop FrameTimeRecording for telemetry usage
According to MSDN documentation, the count of the style array passed to
ExtCreatePen is limited to 16. When we call ExtCreatePen with cStyle=17 or more,
it simply returns an error and the cairo surface used for printing is getting
into an error state, after which nothing further gets printed.
Instead of erroring out, this code change returns an unsupported status so that
cairo will provide fallback handling for it.
This addition of a closure point (explicitly completing the closed shape) isn't
strictly needed in our current cairo version as it works perfectly fine without,
but if our clipping extents code changes then this might cause problems if the
extra point isn't added (in case of 0-length paths).
This extension allows us to get font hint metrics without having to create and
destroy cairo font options structs. Since this is used in loops, this will
improve performance, especially in documents which have many text segments.
Defining _POSIX_C_SOURCE to 199309L on FreeBSD causes compile errors, because of
an obscure interaction between system wrappers and libc++ headers. The source
doesn't seem to need it at all, which tests confirm.
I bet that this is not needed either on other modern systems (even those based
on glibc), and that the define could probably be entirely removed. Not trying
it because I can't test it myself.
ScrollbarStyles contains values of overflow, (over)scroll-behavior, etc.
The only one which is marginally related to scroll _bars_ is overflow, which can
be used to hide scrollbar (by making an element not scrollable) or enforce the
scrollbar to display.
It makes more sense to be called ScrollStyles as it's mainly concerning behavior
of scrolling, not scrollbars. Also, with the addition of scrollbar width
properties, the current name can be confusing.
Since these are just interpreted comments, there's 0 impact on actual code.
This removes all lines that match /* vim: set(.*)tw=80: */ with S&R -- there are
a few others scattered around which will be removed manually in a second part.
