There are always some ridiculous arguments between China and Japanese officials whenever they have the chances to talk. It may represent the domestic conflicts between the political parties, but one might argue whether the cause could be this subtle as symbolic official prayer to war heros, especially the claims are from China, of all the countries in the whole world on earth.
I happened to stand in the position those public figures should not officially favor one religion or the other (think of whatever the woe that would cause to non-believers), and the shrine does remind me of the war time cult-like state of the country. Yet, there are hardly any reason why that should in the way to negotiate political matters between the two countries.
There are other imminent and more demanding agenda that should be settled over such talks. Human rights. Natural resources. Copyright infringements. The exchange rate of yuan. Tariffs. Those issues deserve more attention and the results of the negotiation will matter more to the people in both countries.