In Chrome Canary now you can limit the network throughput. This can be done in the "Network" options of the "Emulation" tab of the Console in the Dev Tools.
You might need to activate the Chrome flag "Enable Developer Tools experiments" (chrome://flags/#enable-devtools-experiments) (chrome://flags) to see this new feature. You can simulate some low bandwidth (GSM, GPRS, EDGE, 3G) for mobile connections.