cef_time_t callbacks not defined

[fluffynukeit]

cef3 callbacks returning cef_time_t are not implemented. Trying to define them results in "unacceptable return type in foreign declaration" errors. I believe this is because the Haskell FFI cannot return structure by value. Since the CEF3 framework invokes these callbacks, they must return a structure by value because CEF expects them to. I do not know how to reconcile this, if possible.