the video is edited, right about when he's showing process explorer post-exploit. the cursor suddenly leaps across the screen, so assuming they're covering up the other child process of the main chrome process is fair. strangely, process explorer's 'process count' only goes up by 1, despite launching calc, and (seemingly) another child process. To be over-zealous, the single row of visible pixels for that other process is consistent with rundll32.exe.

That still doesn't mean that it's not a chrome bug - the exploit may use flash to retrieve the payload, make use of flash-js communication, flash-chrome communication quirks etc.