Make asDirectContext public

External clients will eventually have to call this to get access
to a direct context from an SkCanvas or SkSurface (which will
only have 'recordingContext' accessors).

Bug: skia:10441
Change-Id: I10e34081277b685fa59d03e1fce1887f3524e0fa
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/300178
Reviewed-by: Adlai Holler <adlai@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
36 files changed