Just so people know, when a company uses or buys another companies IP, it is not unusual for the selling/giving company to indemnify the purchasing/using company if some sues them over their use of the IP. The fact Google is willing to pay Samsung costs for the IP that Apple is suing Samsung over is not unusual. Also, the purchasing company does not automatically get indemnified, they would have to ask for it, and Google most likely did not offer this to all their licensees. From the sounds of it the agreement that Samsung may have had with Google required them to defend against the lawsuit and do everything they could to mitigate the costs and risk, otherwise, Google would not indemnify them. Meaning Samsung could not throw up there hands and say uncle and give Apple what every they wanted.
This explains why Samsung is fighting so hard to claim the value is much lower, they are not arguing they did not sell a product with IP which they did not have the rights to, and why they claiming it was all Google's fault. Again, Google may not be required to pay unless it can be shown the IP in question was in fact theirs.