Remove color type from promise image proxy callback.

The color type used to influence the GrPixelConfig and the swizzles
used with the proxy and its GrTextures. So we had to create a new proxy
if the same API texture was used to fulfill a promise image of a
different color type. That has all been removed or lifted out of proxies
and into views. So now it is fine to reuse the same proxy/GrTexture with
a different color type.

Also remove unit test that checked required a new GrTexture be made if
a different color type was used.

Bug: skia:10078

Change-Id: Ib74c419b5d54d382ea95720af7026640e35013f0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281056
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
5 files changed