The failure is due to when we initialize variables to 0, we re-create
the struct TType, and it contains a different unique id from the
original struct TType, thus leading to a different hashed name.

BUG=chromium:641129
TEST=webgl_conformance,webgl2_conformance

Change-Id: I267b97fa496f55ea59dacee93af8f6a90f3e66cb
Reviewed-on: https://chromium-review.googlesource.com/409602
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>