Here are all the patent cases in which Google was a plaintiff. They appear to all be declaratory judgments against NPE defendants.

4:2004-cv-04922 Google Inc. v. Skyline Software Systems Inc. 5:2005-md-01654 In re Compression Labs, Inc., Patent Litigation 5:2004-cv-03934 Google Inc. v. Compression Labs Inc et al 4:2008-cv-04144 Google Inc. v. Netlist, Inc. 3:2009-cv-00642 Google Inc. v. Traffic Information LLC 1:2011-cv-00175 Microsoft Corporation et al v. GeoTag Inc. 1:2011-cv-00637 Google Inc. v. Sourceprose, Inc. 4:2009-cv-01243 Google, Inc. v. EMSAT Advanced Geo-Location Technology, LLC et al