Fix issues related to backend texture/rendertarget creation

Change-Id: I640ea5f316e9e4aba778f450655e74636199e0b1
Reviewed-on: https://skia-review.googlesource.com/76440
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
2 files changed