Establishing CA residency is two-parts subjective and one-part objective LOL.  One might interpret FTB code as the couple's "intention". According to CA FTB tax code it depends on where married couple is domiciled. But also whether or not a spouse spent enough time in the state during the tax year and/or if a spouse earned any income from a California source.   Since OR is not a community property state, if OR spouse earned ONLY from non-CA source and never resided in CA then the couple would file a 540NR, and California Schedule CA NR on which they'd denote spouse A as a full-time CA resident and spouse B as a non-resident, as well as make the necessary income adjustments (Federal vs. California).  

Hope this gets at the question.