Focus object signals stop being sent after a call to Qt.openExternalUrl()

[Michael Sheldon]

When integrating with the input framework for OSK usage, the focus object needs to be set via a call to setFocusObject() on the QInputContext interface. This is done internally by QGuiApplication. This functions correctly within oxide until a call to Qt.openExternalURL() is made by a webapp, after this the setFocusObject() method is never called again and so the keyboard won't display until the webapp is restarted.

We currently have a workaround for this in https://code.launchpad.net/~michael-sheldon/oxide/input-focus-fix/+merge/222507 however further investigation is required to determine the underlying cause of the issue (which may be in oxide or might be in QtUbuntu)