TORONTO — The Conservative Party was criticized by some of its own members on Saturday for a “tasteless” ad put out targeting Liberal Prime Minister Justin Trudeau, a day before he is expected to call an election in the hope of securing a majority in Parliament. “The only reason for an election is because Trudeau wants a majority,” reads the tagline of the 37-second ad released on Friday. The video shows Trudeau’s head pasted on top of Veruca Salt, a character from the 1971 film “Willy Wonka and the Chocolate Factory,” in which she throws a fit for not getting what she wants. The ad drew anger online, with some viewers calling it tasteless. Later, some Conservative members of parliament expressed their dissatisfaction.