When innerWindow is restored from the history state, we do not receive
content-document-global-created notification, but would still like to know
that window is now using a different inner window to reset the state.
This introduces a new notification juggler-dom-window-reused.
At the same time, goBack()/goForward() sometimes do not initiate
navigation synchronously, so our check for pendingNaivgationId() does
not work. Instead, we rely on canGoBack, and assume that client will
not need the navigationId synchronously.
This change introduces NetworkRequest object that encapsulates
internal redirects as they happen in netwerk/ stack.
NetworkRequest now serves as both ResponseBodyListener and NotificationCallbacks.
