Adjust Mock backend's Protected implementation

In order to support GrBackendTexture/GrBackendRenderTarget::isProtected() the protected status needs to reside in GrMockTextureInfo/GrMockRenderTargetInfo. This change bubbles out through the Mock backend.

Bug: skia:14298
Change-Id: I3a12309a6a4ba62fbe423e0dd0f85de0feddbb1b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/696296
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
8 files changed