Adds the glStencilThenCover* nvpr methods to GrGLInterface and starts
using them. When drawing multible paths, this will make it so we only
have to send the index/transform data once. It will also allow the
driver to save time internally.
The glStencilThenCover* methods are a newer addition, so they aren't
available on every driver. In the event that they are not present, we
emulate them using the existing glStencil*/glCover* methods.
BUG=skia:
R=markkilgard@gmail.com, bsalomon@google.com
Author: cdalton@nvidia.com
Review URL: https://codereview.chromium.org/423173004
c8f5204667