Chrome Version       : 56.0.2924.87 (Official Build) (64-bit)
URLs (if applicable) :
Other browsers tested:
  Add OK or FAIL, along with the version, after other browsers where you
have tested this issue:
     Safari: OK 10.0.2 (12602.3.12.0.1)
    Firefox: FAIL 52.0 (64-bit)

What steps will reproduce the problem?
(1) Execute the following JavaScript:
for(let i = 0; i < 10000000; i++) {
  window.history.replaceState({}, null, location.href)
}

What is the expected result?
Lock up the current tab.

What happens instead?
Entire browser application is locked, can switch between tabs but not interact. Cannot open new tabs. Cannot kill offending tab via Chrome's Task Manager.

Please provide any additional information below. Attach a screenshot if
possible.

Firefox exhibits the same result, though eventually asking if you want to kill a long-running script, it remains locked after attempting to kill the script.

Safari displays the following warning in the developer console: SecurityError (DOM Exception 18): Attempt to use history.replaceState() more than 100 times per 30.000000 seconds