[canvaskit] POC working on Node.js

Basically no hoops to jump through - the same binary
that works in the browser works in Node.

Tested locally with Node 8.9.3.

This aligns the GPU and CPU APIs (that is, makeSurface)
and breaks out the GPU/CPU js interface parts into
their own files. We only need one of them and we know
which at compile time.

Bug: skia:
Change-Id: I6d141387403a792d2374cf904872c6dbc999abfb
Reviewed-on: https://skia-review.googlesource.com/c/162746
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
10 files changed