[skottie] Reduce CompositionBuilder stack footprint

LayerBuilder has grown to be pretty chunky.  Using inline storage
SkSTArray<64> in stack-allocated CompositionBuilders is excessive
(and unnecessary).

-fstack-usage before:
  AnimationBuilder::attachPrecompLayer() 7536

-fstack-usage after:
  AnimationBuilder::attachPrecompLayer() 368


Change-Id: Ia905d58e02519d9251620f3eeedbbdc434e3392d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/319342
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed