Revert "Remove Gr*Gpu includes from header files."

This reverts commit 2bd381bffd36cdcffacf606d952547ce66fed7e9.

Reason for revert: Need to revert change this landed on top of

Original change's description:
> Remove Gr*Gpu includes from header files.
> 
> Some general cleanup to try to keep use of the backend gpu class in cpps.
> 
> Bug: skia:
> Change-Id: I1a28e0e5c2e55562b3fff56c284c3405b5b6d8bc
> Reviewed-on: https://skia-review.googlesource.com/20057
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,robertphillips@google.com

Change-Id: I5b27d50654a17502c056d59b2d4f9609376d189e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/20064
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
10 files changed