Use 'inout' qualifiers in generated HLSL for 'out' parameters. With our added padding to some structures, using only 'out' in the generated HLSL can cause warnings because not all of the structure members are initialized. BUG=angle:286 Change-Id: I866960883de487f19883fb2bc086c02703ea6271 Reviewed-on: https://chromium-review.googlesource.com/201364 Reviewed-by: Nicolas Capens <nicolascapens@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>