App Version: 59.0.3064.0 canary
iOS Version: 10.3, 10.2, 9.3.5
Device: iPhone7,  iPad
URL: 

This is originally reported for desktop https://bugs.chromium.org/p/chromium/issues/detail?id=527290

window.location.assign("//") or window.location.replace("//") opens a new tab with about:blank.
These methods shouldn't start a navigation and throw an error.

Code snippet:
<br><div onclick="test()"><h1>Test</div>
  <script>
    function test() {
      window.location.assign("//")
    }
  </script>

Actual Result: Tab navigated to about:blank 
Expected Result: No navigation, No Error

Number of times you were able to reproduce: 5/5
Bug reproducible after clean install: YES
Bug reproducible after clearing cache and cookies: YES
Observed behavior in Chrome Mobile on Android: NO (No error, No Navigation)
Check for similar behavior on Dolphin/Safari/Atomic:
Safari: Alert saying "Safari cannot open the webpage because the address is invalid", No Navigation
Firefox: Alert saying "Firefox cannot open the webpage because it has an invalid address", No Navigation

Bug reproducible on current stable build (App Version, iOS Version): M57 Yes
Bug reproducible on the current beta channel build (App Version, iOS Version): M58 Yes