For a graphical interface, try throttled.
Considering you are savvy, you can could also get creative with builtin OS tools, as detailed below.
I say creative because, to the best of the knowledge, they don't let you throttle specific applications, but you can throttle ports and addresses.
ipfw
Using ipfw to throttle inbound traffic from standard HTTP and HTTPS ports, like so, should throttle Chrome and other browsers:
sudo ipfw pipe 1 config bw 100Kbytes/s
sudo ipfw add 1 pipe 1 src-port 443
sudo ipfw add 1 pipe 1 src-port 80
Remove the rules with:
sudo ipfw delete 1
pfctl
Note, however that ipfw has been deprecated. It still works, but I would really like to give you a comparable command/configuration for its successor pf/pfctl.
Unfortunately, pf is rather obtuse, and I am not certain the current Mac OS X 10.9.2 kernel is properly configured to fully utilize it, vis-a-vis the error:
No ALTQ support in kernel
ALTQ related functions disabled
If you would like to geek out, and get to a non-deprecated solution, here is a five second primer.
BSD's pf (packet filter) is an analog to the Linux tool tc (traffic control), and they allow you to create different types of scheduled queues for network packets.
You may be able to use a Priority Queue to make your greedy application's traffic process first. Or, use a Class Based Queue to explicitly restrict the bandwidth as with ipfw.
http://www.openbsd.org/faq/pf/queueing.html#priq
Other Suggestions
Similar questions asked on other stackexchange sites:
https://apple.stackexchange.com/questions/7426/bandwidth-shaper-or-bandwidth-controller-app-for-mac-os-x
https://apple.stackexchange.com/questions/24066/how-to-simulate-slow-internet-connections-on-the-mac/46378#46378
