Revert "Have a GrBackendFormat be stored on gpu proxies."

This reverts commit 51b1c12bbc2fa3f8d4faa29ad19c6f3cb34837ce.

Reason for revert: reverting till flutter gets to 1.1 to fix build issues.

Original change's description:
> Have a GrBackendFormat be stored on gpu proxies.
>
> Bug: skia:
> Change-Id: Iaf1fb24ab29a61d44e5fa59a5e0867ed02dcda90
> Reviewed-on: https://skia-review.googlesource.com/c/168021
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

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

Change-Id: I574fdc084ef5994596c51fb0d60423b5dc01b885
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:903701 chromium:903756
Reviewed-on: https://skia-review.googlesource.com/c/169835
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
118 files changed