Move shader variables header to include folder. 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/208751 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Zhenyao Mo <zmo@chromium.org>