I don't have a clue about the legislation in CA, but, my bike is street legal here in South Africa.
I have small enduro bike style indicators, no battery. The indicators flash faster as the bike revs up.
I bought my bike new from Yamaha and asked them to install the indicators, so not too sure where they took the power from, prolly the tail light power leads. As the vehicle was purchased new from the dealer, it didn't have to go through any roadworthy inspections at the time.
I was pulled over regularly in the beginning, but now they leave me alone.