If we'd add [SecureContext] to partial interface Navigator and BatteryManager as is the current trend, we could drop the following prose:

If the current settings object is not a secure context, then reject this Navigator object's battery promise with a "SecurityError" DOMException and abort these steps.

However, this would break any feature detection code that relies on checking the existence of properties or objects, e.g.:

if ("getBattery" in navigator && "BatteryManager" in window)
  console.log('All your battery are belong to us');

I guess nearly everyone using this API must do some sort of feature detection.

My hunch is we want to close this issue as won't fix citing backward compatibility concerns.

Thoughts?