463576 - Add a gfxFontGroupCache

Status: RESOLVED WONTFIX

(Core :: Graphics, defect)

Description

[Karl Tomlinson (:karlt)]

A gfxFontGroupCache could be similar to our current gfxFontCache that holds
fonts for a period of time before they expire.

On Linux, I expect this could save an average of around 8-10% on time for
reloading the same page or viewing a similar page (probably on the same site),
due to avoiding the need to repeat font selection.  I don't have an estimate
for other platforms.

The font group is sometimes used as a key to the gfxTextRunWordCache, so
reusing the same gfxFontGroup where possible could provide some savings there
too.

Comment 1

[Karl Tomlinson (:karlt)]

Since bug 703100 there is no longer a gfxTextRunWordCache, but I expect this bug is more important now that bug 703100 removed font selection caching.