Like many roads and places in Colombo, the Viharamahadevi Park is a rename of a park created by the British. Originally named Victoria Park after Queen Victoria, it was renamed in 1958 in honour of a different queen, a Sri Lankan one rather than a British. This is quite similar to what happens in former British colonies. I suppose the name Viharamahadevi was chosen so that the initials V.P. can be retained. I visited the park with members of AsiaExplorers during our tour of Sri Lanka.
Viharamahadevi, the girl who would be queen, was born poor, and was cast adrift as a sacrifice to favour the gods. she was rescued off the coast at Kirinda by King Kavantissa, who took her as his wife. Her only significance in history is for having a son, Dutugemunu, who managed to wrestle Anuradhapura back from the conquering Cholas of South India and united Sri Lanka for the first time.