Well, how about a mix?
It could be feasible that the chromatic dragon could be raised to be good, but like any other creature that has its own identity, it'll want to meet, know, and learn of its heritage/background. It could be feasible that it could revert to evil once again, seeing its human "parent" as nothing more as a captor that slew its parents and enslaved it from birth (thus, possibly vindicating the evil tendencies it may have, or at least those held by those of its ilk).
The Sanctified Creature template from Book of Exalted Deeds seems like a viable option, but it seems that has to deal with converting an evil creature to good (presumably after it has grown up a bit).
I'd suggest both options--the ranger can raise it to be good, but the creature should gain the Sanctified Creature template (by exposure to a sanctify the wicked spell) to avoid/lessen any chances of it returning to evil again.
The poor creature will most likely be an outcast--not trusted by good dragons (except for a few knowledgeable & forgiving few), hated/loathed by evil dragons, and only regularly receiving love & acceptance from the ranger & a few close others (the rest of the party).
I'd also say that the attitudes of the rest of the group will affect the creature's chances as well--something else to keep in mind.