Minimal test case for iframe not rendering (Chrome bug https://code.google.com/p/chromium/issues/detail?id=481922). Repro'd on Chrome 43.0.2357.130 Mac and Windows.
Seems like higher network latencies is required (e.g. 450Kbps, RTT >= 150ms). Server with built in 200ms delay (http://localhost:8000):
./serve.py
Or use network throttling to achieve this with Chrome Dev Tools (screenshot):
Hosted example at https://talee.github.io/iframe-not-rendering/
iframe with text inside (screenshot below)
iframe not rendered (shows as white)
Forcing repaint (in this case resizing browser window width) shows the text.