Move GrAtlasGlyphCache over to SkArenaAlloc from SkVarAlloc.

Change-Id: Ibeee7235d30c68be9fd4f68ecf30a65c7ecb78f5
Reviewed-on: https://skia-review.googlesource.com/13020
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Herb Derby <herb@google.com>
2 files changed