This code fails on windows bots and doesn't print any error: 
std::string script = base::StringPrintf(
  "var %1$s_%2$s_event = 0;"
  "document.getElementById('%1$s').on%2$s = function() {"
  "  %1$s_%2$s_event = 1;"
  "};\n",
  element_name, event);
https://codereview.chromium.org/2750323003/#ps40001 (	chrome/renderer/autofill/password_generation_test_utils.cc)


This code works:
std::string script = base::StringPrintf(
  "%s_%s_event = 0;"
  "document.getElementById('%s').on%s = function() {"
  "  %s_%s_event = 1;"
  "};",
  element_name, event, element_name, event, element_name, event);

What is the expected result?
The code should work since it works on Linux, or print a error message.

What happens instead?
The code fails w/o any output.