Earlier I discovered a simple method to use just chrome for multiplayer testing.
Before I could only use a chrome browser combined with a firefox to test webtrtc locally.
Firefox is very laggy with some events, and sometimes a bit of a pain to work with but needed.
Webkit keeps giving me issues as it thinks its talking to itself partially.
Earlier I found the shortcut combination in Chrome CTRL + SHIFT + N , which opens a incognito window, using its own cookies etc.
If you have your construct 2 preview started with your regular chrome, hit CTRL + SHIFT + N, and a new chrome opens.
Type the addres you use for preview: ie localhost:50000 and voila, you can multi player with just chrome(s)