Add missing include to mojo_fuzzer_message_dump.cc

This happens to fail on Fuchsia, but is just generally not IWYU.

Bug: 808287
Change-Id: I46c8527f0becf79d10c4e960a083e4b9e8eb8bc7
Reviewed-on: https://chromium-review.googlesource.com/c/1298241
Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602502}
1 file changed