Reland "Take GrContext private, GrDDLContext inherit from GrRecordingContext"

This reverts commit 89bdc90ac877dc8cd49c86c35a20d9df0d3b9016.

Reason for revert: Fix metal

Original change's description:
> Revert "Take GrContext private, GrDDLContext inherit from GrRecordingContext"
>
> This reverts commit d2daa94edeca88281796524fae45f38f11a7bef2.
>
> Reason for revert: Metaru
>
> Original change's description:
> > Take GrContext private, GrDDLContext inherit from GrRecordingContext
> >
> > Woo!
> >
> > Change-Id: I8d201b709343dc18cad31ea740575285dd035f35
> > Docs-Preview: https://skia.org/?cl=317436
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/317436
> > Reviewed-by: Robert Phillips <robertphillips@google.com>
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Commit-Queue: Adlai Holler <adlai@google.com>
>
> TBR=bsalomon@google.com,robertphillips@google.com,adlai@google.com
>
> Change-Id: I9b58dee285fbdc49ebc8e76df5da0fe224cf9787
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/318758
> Reviewed-by: Adlai Holler <adlai@google.com>
> Commit-Queue: Adlai Holler <adlai@google.com>

TBR=bsalomon@google.com,robertphillips@google.com,adlai@google.com


Change-Id: Id4b10795193a904cd4ed8c36e60e74abe3b6702a
Docs-Preview: https://skia.org/?cl=318759
Cq-Include-Trybots: luci.skia.skia.primary:Build-Mac10.15.5-Clang-arm64-Debug-iOS_Metal,Build-Mac-Clang-x86_64-Debug-Metal
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/318759
Commit-Queue: Adlai Holler <adlai@google.com>
Reviewed-by: Adlai Holler <adlai@google.com>
11 files changed