Fix up GrGlyphCache ctor

It looks like the old GrGlyphCache ctor was making an
initial arena alloc of 9 bytes.

Change-Id: Icc0d04c522fc1f90bf06bdfe5bd6ef56315776ac
Reviewed-on: https://skia-review.googlesource.com/c/173232
Reviewed-by: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
2 files changed