come upon vs pass by

come upon

verb
  • To befall; to affect; to happen to. 

  • To discover or find, especially by chance or accident. 

pass by

verb
  • Of a period of time: to come to an end, to elapse. 

  • to drop by 

  • To travel past without stopping. 

  • To travel past (something) without stopping; to ignore, to disregard. 

How often have the words come upon and pass by occurred in a corpus of books? (source: Google Ngram Viewer )