Add ctor to GrVkAlloc

TBR=bsalomon@google.com

Bug: skia:
Change-Id: I7b4b372674df6ff43f737ac1b3f2f63b87719b6a
Reviewed-on: https://skia-review.googlesource.com/111660
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
1 file changed