We need to keep a better eye on the leak output. One way to do this would be to run a script to classify the leaks, and count the number of unique leaks.
Created attachment 81096 [details]
Here's a really basic uniq-leaks tool (written in 2009 in Perl) that attempts to uniq leaks output.
It just needs to be hooked up to old-run-webkit-tests --leaks.
I just posted a tool in bug 56028 that makes viewing leaks output easier. It's not really set up for use in an automated fashion, however.
Some more ideas:
1) Use the uniq-leaks tool attached to this bug to show the number of unique leaks in the run-webkit-tests --leaks output, and also put that output on build.webkit.org
2) Show more information about leaks that have WTF::fastMalloc in the stack. These are leaks of JSC/WebCore/WebKit objects, and it should be pretty easy to say which objects and how many of each kind are leaking.