Bug 1575969. In PHP7 some errors throw an Error object (to
the exception handler) instead of generating an error
(handled by the error handler). The official way to make
an exception handler that will work in PHP 5 & 7, is to
leave off the parameter's type declaration.

Change-Id: I5fc1c3765d5a311eb499d62915e676f8d9ee07a0
behatnotneeded: Covered by existing tests