Add ability to specify different GP textures for each mesh in a draw.

Uses GrPipeline::DynamicStateArrays to allow per-mesh GP textures when
drawing an array of GrMeshes.

Uses this along with op-chaining to make drawing multiple TextureOps
with different textures faster.

Change-Id: Iec4da1b72a13d0e0c94c8a8568fe4221c539dfcf
Reviewed-on: https://skia-review.googlesource.com/145960
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
18 files changed