Simulate limited bandwidth from within Chrome?

Starting with Chrome 38 you can do this without any plugins. Just click inspect element (or F12 hotkey), then click on toggle device mod (the phone button)

and you will see something like this:

Among many other features it allows you to simulate specific internet connection (3G, GPRS)

If you are running Linux, the following command is really useful for this:

trickle -s -d 50 -w 100 firefox

The -s tells the command to run standalone, the -d 50 tells it to limit bandwidth to 50 KB/s, the -w 100 set the peak detection window size to 100 KB. firefox tells the command to start firefox with all of this rate limiting applied to any sites it attempts to load.

Update

Chrome 38 is out now and includes throttling. To find it, bring up the Developer Tools: Ctrl+Shift+I does it on my machine, otherwise Menu->More Tools->Developer Tools will bring you there.

Then Toggle Device Mode by clicking the phone in the upper left of the Developer Tools Panel (see the tooltip below).

Then activate throttling like so.

If you find this a bit clunky, my suggestion above works for both Chrome and Firefox.

I'd recommend Charles Proxy - you can choose to slowdown individual sites, also has a whole bunch of HTTP inspection tools.

Edit:

As of June 2014, Chrome now has the ability to do this natively in DevTools - you'll need Chrome 38 though.

The option is accessible from the Network tab via a drop down at the end of the toolbar.

As of today you can throttle your connection natively in Google Chrome Canary 46.0.2489.0. Simply open up Dev Tools and head over to the Network tab: