SAN FRANCISCO -- Like many gay couples, Brian Cornell and Alberto Rulloda long ago established a legal framework for their relationship to match their commitment to each other. They drew up wills naming the other as beneficiary, property agreements and powers of attorney, among other documents. The couple of 27 years wanted to spell out the specifics that would have been presumed if they were married. Come Saturday, such improvised arrangements will be less necessary for them and nearly 29,000 other California couples -- the majority same-sex partners. A law taking effect with the new year gives gay couples who...