Take origin when creating/updating backend texture using pixmaps.

Bug: skia:11042

Change-Id: I511c7556f97f19d7f162031c245019d2da33c129
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/341005
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
13 files changed