Instead of just {Object}, this field can be typed as
{Managed<wasm::Module>}.

R=herhut@chromium.org

Change-Id: Iad47f75ae823846394b6ad04e8829961e924f33d
Reviewed-on: https://chromium-review.googlesource.com/1102333Reviewed-by: Stephan Herhut <herhut@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53762}