According to a header from a sealed document unearthed by FOSSPatents, Google has requested to intervene in an ITC patent lawsuit between HTC and Nokia as co-defendant to the Taiwanese smartphone-maker. This is the first time Google has ever filed as an intervening 3rd-party in a patent lawsuit between one of its hardware partners and a competitor, so it may be the sign of a shift in strategy for the company.
There's also the fact that Google has requested an antitrust investigation against Nokia in the EU, so maybe Google is just piling on the Finnish firm to makes its stance even more clear. As the case involves patent infringement, Google is likely looking to assert its own portfolio against Nokia, as well as to defend HTC using its own patents where feasible (eg, in issues involving core features of Android, as opposed to HTC devices specifically).
It's probably best not to read too much into this, as lawsuits are by their nature complex entanglements of business strategy and legal technicalities - taking this as a sign of a larger change in philosophy for Google may be a bit premature. We'd all love to see Google jump into the fray against Apple and Microsoft, but it's easy to forget that this would also mean more lawsuits piled on top of more lawsuits. Still, direct intervention may be the only way this mess can get sorted out, and it's possible Google is getting tired of seeing its partners get pushed around with injunctions and import bans.