I have this shell script as `chrome-new` in my path for testing in Chrome and the rare site that is broken in Firefox. It gives me a totally clean profile each time to minimize the amount of Google spying that goes on and reduce my tendency to use the browser for anything but the current task. Sadly despite --no-make-default-browser, it still asks me with an infobar every time I start it.
#!/bin/sh
test -e "$(which chromium)" && CHROME="chromium"
test -e "$(which google-chrome)" && CHROME="google-chrome"
test -e "$(which google-chrome-dev)" && CHROME="google-chrome-dev"
TMPDIR=`mktemp -d /dev/shm/chrome-XXXXX`
$CHROME --user-data-dir=$TMPDIR --no-first-run --no-make-default-browser "$@"
rm -rf $TMPDIR
AFAIK guest mode acts like incognito when it comes to storage behavior (changes stay in-memory and are not persisted to disk, and therefore available storage is noticeably lower than with a regular profile), so it will trigger incognito mode detection scripts on some times.
