child's play vs slam dunk

child's play

noun
  • Something particularly simple or easy. 

  • Used other than figuratively or idiomatically: the play of a child. 

slam dunk

noun
  • A task expected to present no difficulty, a piece of cake. 

  • An impressively forceful dunk. 

  • Tacking on top of the wind of the following yacht in close quarters 

verb
  • To perform a slam dunk. 

How often have the words child's play and slam dunk occurred in a corpus of books? (source: Google Ngram Viewer )