Dave Meltzer of the Wrestling Observer Newsletter is stating that there has been a major confusion regarding who made the call to end the Undertaker's WrestleMania streak. It is almost certain that if Undertaker did not really want it to end, then he would have had a major say in the streak continuing.
However, The Undertaker was scheduled to pick up the victory at WrestleMania XXX until the final few days of planning. At some point, Vince McMahon changed his mind because of the physical condition of The Undertaker. Vince was said to be thinking that this could have been the last match of The Undertaker.
Regarding the conversation between Vince and Taker, nobody knows for sure how the conversation went aside from them two. A friend close to Taker said that he was talked into it, while another source claims that Undertaker said that he did not argue it and accepted it.