PS1 is mostly from luigi@2dimensions.com, with slight re-naming
tweaks (thanks!).
With the exposition of these extra methods, MakeWebGLCanvasSurface
is now really just a convenience function.
Bug: skia:
Change-Id: Ie61657bc580146e3e759fae8620e4df0c0212f62
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/198720
Reviewed-by: Brian Osman <brianosman@google.com>