GLSL 1.017 4.2.4:
Structures must have the same name, sequence of type names, and
type definitions, and field names to be considered the same type.

TEST=conformance/glsl/misc/shaders-with-uniform-structs
BUG=angleproejct:2013

Change-Id: Ieedaaca2d28ef4e1cc0b5480f413ebd513c1dc1f
Reviewed-on: https://chromium-review.googlesource.com/524036
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>