Launch a new, clean and distinct instance of Google Chrome that cannot sync and does not do the first-run dance.

chromeapp.sh

#! /bin/bash

set -e 

[ -z $1 ] && dir='/tmp/foo' || dir=$1
 
chromedev="/Applications/Google Chrome Dev.app"
 
runChromeDev() {
	(
		"${chromedev}/Contents/MacOS/Google Chrome" \
			--disable-sync \
			--no-first-run \
			--user-data-dir="${dir}" > /dev/null 2>&1
		rm -r "${dir}"
	) &
}

chromeDevFirstRun() {
	echo "Performing ChromeDev first run"
	echo "Copying 'Google Chrome.app' to 'Google Chrome Dev.app'"
	
	cp -R "/Applications/Google Chrome.app" "${chromedev}"
	
	local infoplist="${chromedev}/Contents/Info.plist"
	local stringsfile="${chromedev}/Contents/Resources/en.lproj/InfoPlist.strings"
	
	# update info.plist
	echo "Updating 'Info.plist' to create unique instance of Chrome"
	sed -i -e "s/<string>com.google.Chrome<\/string>/<string>com.google.ChromeDev<\/string>/" "${infoplist}"
	sed -i -e "s/<string>Chrome<\/string>/<string>Chrome Dev<\/string>/" "${infoplist}"
	
	# update InfoPlist.string for display names
	echo "Updating 'InfoPlist.strings' to create a unique display name for this instance"
	plutil -convert 'json' "${stringsfile}"
	sed -i -b -e 's/"CFBundleDisplayName":"Google Chrome"/"CFBundleDisplayName":"Google Chrome Dev"/' "${stringsfile}"
	sed -i -b -e 's/"CFBundleName":"Chrome"/"CFBundleName":"Chrome Dev"/' "${stringsfile}"
	
	# uncomment this if you have problems with the display name not being what you expect
	# plutil -convert 'binary1' "${stringsfile}"
}

if ! [ -d "${chromedev}" ]; then
	chromeDevFirstRun
fi

runChromeDev