Make angle perftests build with clang. ::testing::WithParamInterface ends up calling deleting an object with the type of the template parameter, and the pointer it deletes could arguably point to a subclass of the param object -- so clang warns that there's a delete on a class with a virtual method but without a virtual dtor. Make the param classes final to let the compiler know that this can't happen in practice. BUG=chromium:82385 Change-Id: I49a4120b15670d876613b22ba709d50bf4685006 Reviewed-on: https://chromium-review.googlesource.com/261965 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Nico Weber <thakis@chromium.org>