"Assuming this timeline, Philip Morris’ argument nonetheless contains a fatal flaw—a flaw of omission. Although Philip Morris uses the word “delegation” or variations many times throughout its brief, we have found no evidence of any delegation of legal authority from the FTC to the industry association to undertake testing on the Government agency’s behalf. Nor is there evidence of any contract, any payment, any employer/employee relationship, or any principal/agent arrangement. We have examined all of the documents to which Philip Morris and certain supporting amici refer. Some of those documents refer to cigarette testing specifications, others refer to the FTC’s inspection and supervision of the industry laboratory’s testing, and still others refer to the FTC’s prohibition of statements in cigarette advertising. But none of these documents establish the type of formal delegation that might authorize Philip Morris to remove the case.... And, though we find considerable regulatory detail and supervision, we can find nothing that warrants treating the FTC/Philip Morris relationship as distinct from the usual regulator/regulated relationship. This relationship, as we have explained, cannot be construed as bringing Philip Morris within the terms of the statute."