The linked to file is a 1.7meg HTML file. Opening it in Safari with ToT WebKit causes safari's ram usage to increase by quite a large margin.
Closing the page, and then reopening doesn't make it take another 40 mb, so i'm closing as invalid.
The problem wasn't that it was a memory leak, the problem was that it was using almost 40 times the amount of memory to parse the file. The overhead seems exceptionally large for this particular file.
I don't think there's anywhere to go with this.
According to the memory timeline in inspector chrome only uses about 4mb to load this page. So unless someone can show otherwise - there's nothing to do here.