The callback lets the caller know when the data uploads to the texture
from the create call are finished. This is important since the caller
cannot delete the backend texture till the gpu is finished on vulkan
and d3d.
This change also removes the hard sync in vulkan during creation.
Change-Id: I660d142219474e22b1337d2b0c81cda66fe18a4b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/286517
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
c1ad77cf48