The actual comparison would be between the Chrome binary size and the Chromium binary size, which is quite small if you exclude embedded graphical resources.
I don't understand your point. If there were such a difference between Chromium and Chrome, then it would surely show up in a diff of the binaries' disassemblies. The size of the binaries doesn't matter, because (assuming you trust the Chromium source and your local system) only the difference between the two is relevant.
