Record modes let you record every request Chrome makes. Playback mode serves requests out of that recorded cache just as if they were being loaded on the spot. It doesn't record where you click or what you open, just every request as it moves over the wire.
These instructions are tuned for OS X, but can be adapted to any operating system.
1. Start by closing Chrome (after copying down these instructions!)
2. Open a Terminal (Cmd+Space then type "Terminal")
open -a "Google Chrome" --args --record-mode and hit enter.
4. Run through your demo, and close Chrome, returning to the terminal.
open -a "Google Chrome" --args --playback-mode and hit enter.
6. Everything will be served out of the recorded cache, even if your servers have exploded, a bug has been deployed, or the conference wifi has dropped out.
Thanks to commenter Michael Kenniston we have these commands for Ubuntu (and most other Linux):
As with the OS X instructions, remember to close Chrome before beginning and between steps.
Commenter Kristian J. has provided these instructions for Windows:
Press Win+R to open the run dialog, enter
chrome --record-mode for record mode and
chrome --playback-mode for playback.