um... I don't know about California... but mall cops typically don't have much more education of the laws than you or I. Ask a sworn law enforcement officer or call your local precinct for clarification.
Hard to say, I live in California and let me tell you - I wouldn't be surprised it it became legal to stone smokers to death in a few years! The smoking laws are brutal here, and the dirty looks you get from people when you light up, even if you are outside and step away from people so as not to bother anyone with your smoke is ridiculous.
However, I doubt seriously that they have any laws on the book regarding e-cigs at this time, in fact Arnie the Gov recently vetoed a law against e-cigs so more then likely the mall cop was just throwing his weight around, or perhaps the bar owner called the mall cops in because narrow minded people were complaining?