Vulkan: Remove inactive shader inputs in the translator Inactive vertex attributes are harmless to remove. Between two consecutive stages, the input varyings must be a subset of the previous stage's output varyings. This means removing inactive input varyings is also harmless. Removing inactive output varyings is not possible though. GLSL allows a varying to not be written by the previous stage even if it's used in the current stage (values will be undefined, but it's not an error). This means that an inactive output varying may still need to exist as part of the shader interface in case the following stage has that varying as input (and is active). Bug: angleproject:3394 Change-Id: I7302973d2b8356d9f54a66f8259c32f245a99904 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2009986 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>