On advancing the iterator we need to reset the current object,
so that it can be lazily reloaded later on.

TBR=mlippautz@chromium.org

Bug: chromium:694255
Change-Id: If7ddd8670df9d11837f491503312919b55b451fe
Reviewed-on: https://chromium-review.googlesource.com/600687
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47142}