I am in the process of having a patio cover added to my home. The cover will contain 8 can lamps, two ceiling fans, three flood lights and 4 additional 110 volt receptacles. The electrician, (liscensed and bonded) has ran the wiring from a 110 volt receptacle in an adjacent upstairs bedroom which is rarely used. All of this is connected to a single existing20 amp breaker in the breaker box. This particular breaker also serves the rarely but sometimes used bedroom. I have been told by another electrician this is too much on the one breaker, and the new patio cover really needs two dedicated breakers of its own. My original electrician says it is safe. WHO"S RIGHT!! I definitely want it to be safe!! Please help!!

This is way too much for I breaker.

The flood lights and the can lamps will most likely use more energy than the rest of the appliances. If you use CFL's in these areas you can reduce the load considerably.
What do you expect to use the outlets for? Televisions, stereos... either use too much "juice", but if you use electric heaters or room air conditioners, you could have a problem. Figure out what you intend to use in the room and just add up the load.
I'll bet you will be all right.