Stop shader local variables from using invalid qualifiers.

Local variables in GLSL can't use any other storage qualifier than
'const', but we weren't checking properly. For example, the can't
have 'in' or 'out' storage. This was causing a dEQP conformance
test failure.

BUG=angle:593

Change-Id: Ibb333950f2d0990a47d1a96caecc455497d5e57e
Reviewed-on: https://chromium-review.googlesource.com/191460
Reviewed-by: Nicolas Capens <nicolascapens@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
3 files changed