Bind all elements of unbound image arrays to unit zero Spec GLSL ES 3.10, section 4.4.5, Any uniform sampler, image or atomic counter variable declared without a binding qualifier is initially bound to unit zero. If the binding qualifier is used with an array, the first element of the array takes the specified unit and each subsequent element takes the next consecutive unit. BUG=angleproject:1987 TEST=angle_end2end_tests:ComputeShaderTest Change-Id: I6a8188449a91bf3e8ded37e067205dcae4e47fa7 Reviewed-on: https://chromium-review.googlesource.com/547977 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>