For now the Toolbar is still having lot of code related to the location bar in it. They need to be moved to a place closer to the location bar.

This task includes:
- Moving part of the OmniboxFocuser protocol to a dispatcher command protocol (-focusOmnibox and - cancelOmniboxEdit). The other methods can stay inside the toolbar as they are main NTP specific.
- Implementing the VoiceSearchControllerDelegate and QRScannerResultLoading in the LocationBarCoordinator (including the private -loadURLForQuery).
- The LocationBarDelegate protocol should be reworked. The -loadGURLFromLocationBar:transition: method should be implemented by the LocationBarCoordinator (to be consistent with the previous point). The protocol should be merged with WebToolbarDelegate as the toolbar implementation of LocationBarDelegate is mostly forwarding calls to this protocol. The BVC should be the one implementing this new protocol.
- The |_locationBar| ivar should be moved from the toolbar to the LocationBarCoordinator.