Muslims accept that which was revealed to Prophet David (peace be upon him) in its original form, which in the Qur'an is referred to as the Zaboor. Many consider this to be synonymous with the biblical book of Psalms, due to their being attributed to David. So it is often misunderstood that Muslims accept the Psalms, Torah and Gospels in the form that they are found today and this is not the case. Muslims accept them only in their original forms with no alterations whatsoever. The Qur'an is the only Scripture that has been preserved in its original language, having no alteration from the time it was revealed. Therefore, the Qur'an is the yardstick by which all other alleged Scriptures are judged.
Because of the above, I cannot answer the question with certainty. But judging from the context, I would have to say that David is the "son" being referred to in that verse and not Jesus (peace be upon him). This is similar to the other "sons" that are mentioned in the Bible: Luke 3:38; Genesis 6:2,4; Exodus 4:22; Jeremiah 31:9; Romans 8:14.