Fix invalid downcast in nacl_message_scanner.cc

The downcast wasn't necessary at all. We could just remove it. The
pointer is never actually used as a MessageType*, only upcast back to an
IPC::Message*. (There is a "dereference", but it is to pass into a method
taking const IPC::Message&.)

Leave it as an IPC::Message*.

Bug: 520760
Change-Id: I6ac697fc1676bd9bbc754c97e617ce297197432c
Reviewed-on: https://chromium-review.googlesource.com/c/1298455
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: David Benjamin <davidben@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#602752}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: bf3962f083e3f69330474d15bd2718c195e2e375
1 file changed