[Fontations] Hold on to Path target arrays to avoid alloc churn

Avoid allocation churn, but also keep allocated size in check by holding
on to path extraction target buffers. If a glyph with large contour
count occurs, this is cleaned up after the path got transfered to the
SkPath that holds on to the arrays.

Improves path extraction performance by about 3%.

Bug: skia:370024633
Cq-Include-Trybots: luci.skia.skia.primary:Build-Debian10-Clang-x86_64-Debug-Fontations,Build-Mac-Clang-x86_64-Debug-Fontations,Test-Debian10-Clang-GCE-CPU-AVX2-x86_64-Debug-All-NativeFonts_Fontations,Test-Mac12-Clang-MacBookPro16.2-CPU-AppleIntel-x86_64-Debug-All-NativeFonts_Fontations
Change-Id: Ie3c42e5a50b536d8ca950bf972ad86e49858d382
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/905157
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Dominik Röttsches <drott@google.com>
Reviewed-by: Dominik Röttsches <drott@google.com>
2 files changed