In the following patch we are going to change the signature of
ShouldSanitizePreference to take a Pref object. Pref is only
known to the Preferences compilation unit; so to keep this member
(whose signature will change) we would need to expose the Pref
class. However it will only be a forward declaration, one could
not construct a Pref object in e.g. the gtest.
It is simpler to just remove the member entirely and call
ShouldSanitizePreference unconditionally - the member was only
used for the gtest, and while the gtest will be less robust
because of this change, it will still do some testing.
Depends on D141419
Differential Revision: https://phabricator.services.mozilla.com/D141420
3313c98eaf