Only initialize globals if initialization flag is set This avoids the possibility of initializing globals twice in Chromium. Now we also never initialize variables redundantly in case we're writing HLSL output. This was already the intent of the code before, but a mistake had slipped in and the code didn't actually check the output type properly. This also simplifies DeferGlobalInitializers by running it after SeparateDeclarations. BUG=chromium:735497 TEST=WebGL conformance tests Change-Id: I95036a24ac8cf18113755510376a2fca286b3ee6 Reviewed-on: https://chromium-review.googlesource.com/771555 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>