No need to define a function just to default-initialize all fields.

R=mstarzinger@chromium.org

Bug: v8:7754
Change-Id: I059f310d22435a364dff8b7cfcb68c6314412c9a
Reviewed-on: https://chromium-review.googlesource.com/1136306
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54438}