Typically music that plays in restaurants is chosen by the brand owners or product marketing managers for the brand or hotel chain. The larger ones mostly work with curated music providers to choose playlists that are chosen to match the restaurant / store / hotel brand’s demographic / image / style and the music is day parted (organised so that it plays the right styles / tempos etc of music at the right time of day).
Companies that specialise in curated music content vary in size from multinationals, including Mood (who I think own Pandora), PlayNetwork (US/UK based) and other independents including Perfect Octave (UK/EUR), Music Concierge (UK), Imagesound (UK) and others.