using dimensions on components that get moved to popout windows has wrong window reference

[Dimitar Christoff]

simple usecase

using react-popout (https://github.com/JakeGinnivan/react-popout) to tear off components into popout windows, which basically unmounts it and then re-mounts it into a new window and a new document.

the problem is this code: https://github.com/digidem/react-dimensions/blob/master/index.jsx#L110

window.addEventListener('resize', this.onResize, false)

... may resolve the window object too early and to the parent (original window), therefore adding the event to the wrong one.

subsequent resizes of the popout window do not trigger the resize and dimensions do not update but if the popout.opener gets resized, it fixes the popout dimensions.