Remove SkImage_GpuBase::getTexture().

Part of effort to consolidate access to GPU SkImage texture proxies.

Bug: skia:11208
Change-Id: Icfcf6fea6be6f05220a5ddd1482f88dafe1cbd9d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/359836
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
5 files changed