Shift-Tab does not cycle focus backwards through web elements

Pressing tab in a WebEngine view will advance focus according to tab order, however holding shift and pressing tab does not cycle focus backwards which is standard behavior.

I'm not sure if it's related but the `code` and `key` values of browser keydown events is inconsistent between QtWebEngine and Chrome. See attached screenshots, in both I loaded the page, pressed tab, then shift-tab. The page logs a subset of the keydown event's properties. For some reason in QtWebEngine we get "KeyS" for code any time tab is pressed and "\u0019" for key when shift-tab is pressed.