Even in the best of California’s economic glory days, no governor has entered office with the kind of fiscal tail wind that Gov. Gavin Newsom now enjoys. The government’s coffers are full of taxpayer cash, its reserve accounts are stocked to weather an economic slowdown and there’s general consensus on new help for the state’s youngest and most vulnerable residents. A major political victory would seem all but assured as he prepares to unveil a revised state budget this week. And yet, Newsom’s very real challenge is a quandary of quantity: more tax revenue, yes, but also more Democrats in the Legislature after last year’s election landslide and more demands to raise spending.