Nobody,
As I've explained before, any attempt to change accounting treatment because cash is diverted from point a to point b will fail accounting rules. If the contract states that royalties are due, then that should be revenue regardless of whether the debt is paid now or in 1 years time. Now, the parties can, of course, structure a new revenue agreement at any time, however, I should have a thought a restructured agreement with the largest client would constitute a significant event that should be publicised.