This is partial support for CHROMIUM_path_rendering
and implements basic path management and non-instanced
rendering.

BUG=angleproject:1382

Change-Id: I9c0e88183e0a915d522889323933439d25b45b5f
Reviewed-on: https://chromium-review.googlesource.com/348630Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>