Empty declarations are possible in loop init expressions. Make PruneEmptyDeclarations take this into account. BUG=angleproject:1550 TEST=angle_unittests Change-Id: If407babf9b6f7a26dfcf73ff345493d3e2af3f9a Reviewed-on: https://chromium-review.googlesource.com/401147Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>
