Iterate over all descriptors instead of bailing out early and missing
enumerable properties later.

Bug: chromium:836145
Change-Id: I104f7ea89480383b6b4b9204942a166bdf8e0597
Reviewed-on: https://chromium-review.googlesource.com/1027832Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52786}