Using DCHECK seems to be the common V8 style.

Change-Id: I6dab91e5225a222cbfe07ebeeec4ed1b274fe5bd
Reviewed-on: https://chromium-review.googlesource.com/1088698Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Stephan Herhut <herhut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53554}