Google, Spotify, Apple, Amazon and other music service providers went hat-in-hand to the music industry poobahs and negotiated contracts for the rights to stream their songs. It wasn’t cheap, nor was it easy to deal with big egos and inflated financial expectations in the record business. But now those tech companies have access to the most important part of the supply chain. Pandora wants the same deals now, and now must negotiate music-industry deals from scratch. That won’t be simple at a point when it has almost no leverage because of rising competition for listeners and for song rights — and because the music industry hates Pandora.