The class extends the QDDebugService class, _not_ QDDebugServer. It's
right that there is also a QDEngineDebugServer being actually a service
in QtDeclarative, but we should probably fix this one too.
Don't force users to inherit from QDeclarativeDesignView. Instead we're
using now event filters to let a user attach a QDeclarativeViewObserver
object to a QDeclarativeDesignView.