Revert "Revert "Support creation/use of mipped proxy in GrBackendTextureImageGenerator""

This reverts commit 7477d9693869982a4b0b18d20fee32d2f3eaedbf.

Reason for revert: Putting in fixes in tests

Original change's description:
> Revert "Support creation/use of mipped proxy in GrBackendTextureImageGenerator"
> 
> This reverts commit b8ad00b5a68975cafd68d6df0d66f0a01f5c07c2.
> 
> Reason for revert: Some various test failures 
> 
> Original change's description:
> > Support creation/use of mipped proxy in GrBackendTextureImageGenerator
> > 
> > Bug: skia:
> > Change-Id: I9d06780ccb2db0865100b67041c03408f2445c62
> > Reviewed-on: https://skia-review.googlesource.com/61241
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Commit-Queue: Greg Daniel <egdaniel@google.com>
> 
> TBR=egdaniel@google.com,bsalomon@google.com,brianosman@google.com
> 
> Change-Id: I28e625776352ee6f9f27e66cd5d4b149ef50a22a
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: skia:
> Reviewed-on: https://skia-review.googlesource.com/61941
> Reviewed-by: Greg Daniel <egdaniel@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,brianosman@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: skia:
Change-Id: Ibfbca5101b06d9ff8f8a5d33bc6f2114806db552
Reviewed-on: https://skia-review.googlesource.com/62561
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
5 files changed