Add interface to draw multiple paths in a single "command" to a draw
target. Implement this interface in GrGpuGL with NVPR "instanced"
calls.
The instanced calls accept list of paths and list of transformations as
their parameters. The transformations are at this moment expected to be
2d affine transformations, as the functions are called only for text
rendering.
This will be used when drawing fonts. Later it can be maybe be used in
GrInOrderDrawBuffer to aggregate many draw calls into one instanced draw
call, similar to drawing rects.
R=jvanverth@google.com, bsalomon@google.com
Author: kkinnunen@nvidia.com
Review URL: https://codereview.chromium.org/209413006
git-svn-id: http://skia.googlecode.com/svn/trunk@13930 2bbb7eff-a529-9590-31e7-b0007b416f81
9b62aa156b