c01ceb0e75
Motivation: DefaultCookie currently used an undocumented magic value for undefined maxAge. Clients need to be able to identify such value so they can implement a proper CookieJar. Ideally, we should add a `Cookie::isMaxAgeDefined` method but I guess we can’t add a new method without breaking API :( Modifications: Add a new constant on `Cookie` interface so clients can use it to compare with value return by `Cookie.maxAge` and decide if `maxAge` was actually defined. Result: Clients have a better documented way to check if the maxAge attribute was defined.