do not override up/down arrow keys

What steps will reproduce the problem?
1. open a code review
2. try to scroll down by pushing down arrow

What is the expected output? 
page scrolls down.

What do you see instead?
a little line moves down the screen.

Alternate steps:
1. open code review
2. page down a few pages
3. try to scroll up or down with arrow keys

What is the expected output? 
page scrolls up or down.

What do you see instead?
If you push down arrow, nothing happens.
If you push up arrow, page jumps back to top of file.

What browser are you using?  What version? On what operating system?

Google Chrome   20.0.1130.1 (Official Build 135886) dev
OS  Linux

At what URL are you accessing Rietveld?  (e.g. codereview.appspot.com)
Please note if you are using the Google Apps Labs version (e.g.
codereview.<yourdomain>).
codereview.chromium.org

*** If you are a Google employee please say so or mail me (Guido van
Rossum) directly. ***
yes

Original issue reported on code.google.com by mattm@chromium.org on 11 May 2012 at 9:45

Merged into: #378

v3ss0n / rietveld

do not override up/down arrow keys #380