Fix mock tex rt gpu mem size

Change-Id: Ieeab32d3eb8fdbb16c004537f2d50956d6ec74d3
Reviewed-on: https://skia-review.googlesource.com/102022
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
2 files changed