American Ballet Theatre is the tutu-wearing, toe-shoed, 800-pound gorilla in the studios of American ballet. Armed with a repertory of the great full-length ballets of the 19th century, ABT stages these works with maximum opulence and impeccable grace. For its appearance at the Dorothy Chandler, the company trots out the old war horse Swan Lake, as choreographed by artistic director Kevin McKenzie. The story may be all-too-familiar, but the ABT's principal virtuoso dancers leave a lasting, beautiful impression.