This allows the API to query for clear type introspection into the
parsed GL types from the translator. The returned types are not
expanded and have properly nested fields.

This patch uses the types from ShaderVars.h to return GL type
information. The app must include this header to get access to
the types structs.

BUG=angle:466

Change-Id: I28ad0d6f11a964804dd234ef0d00651f665d1ae3
Reviewed-on: https://chromium-review.googlesource.com/208751Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>