Google could agree to indemnify app developers for legal fees. There are certain restrictions on other people paying for your legal defense but it's commonly done subject to those restrictions.
They could also take the first app developer to get sued under the patent and pay for them to file a CBM review. Or file an IPR or PGR in their own right seeking to invalidate the patent.
If Google just paid for the defense of the developers, without patent reform, wouldn't that just encourage more patent trolls to arise, knowing there is a massive pot of gold?
Only if the trolls won. On the other hand, if Google's lawyers gave them the smack down then all the patent trolls would go scurrying back under the rocks they crawled out from
Even when trolls lose, they're typically shell companies with no assets, so they can't pay for the legal fees of the winner (they just go bankrupt) and the winner still loses in terms of money.
Spin off a shell corp for each individual patent that is litigated, if a loss ever occurs, the only thing "on the line" in a bankruptcy is the single patent that presumably just lost.
They could also take the first app developer to get sued under the patent and pay for them to file a CBM review. Or file an IPR or PGR in their own right seeking to invalidate the patent.