Fix Chrome workaround to work in the context of the extension
Fix Chrome workaround to work in the context of the extension

Fix the previous workaround to work in the context of the extension
where `document` is the background page but the selection in the popup
window (`clipboardDocument`) needs to be cleared.

robertknight/passcards,robertknight/passcards,robertknight/passcards,robertknight/passcards