This is to protect against cases where part of a project is
compiled with or without this flag, making for very fragile
and hard to find bugs, such as sizeof(Verifier) changing.

Change-Id: I01c895cdc5b44f860e4b0b9c9613bff1983e2b9d
See: https://bugs.chromium.org/p/chromium/issues/detail?id=929847