Handle mipmap creation failure in DDL test harness

SkMipMap::Build fails surprisingly often. Fall back to unmipped promise images in that case.

The prior approach created the mipMaps too late (i.e., at backendTexture creation time) for the test harness to change its mind about the mip status of a promise image. This approach moves the mipmap creation earlier - to when the PromiseImageInfos are created (i.e., at SKP deflation time).

Change-Id: Id3c67a44cc84da7ee76d02f4d44d7f27ce8e39d6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/284136
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2 files changed