r84147, 2001 leaks http://build.webkit.org/builders/SnowLeopard%20Intel%20Leaks/builds/16327 r84152, 6343 leaks http://build.webkit.org/builders/SnowLeopard%20Intel%20Leaks/builds/16328 Check out the "view leaks" URLs on those build pages to see the leaks.
Most/all of the leaks seem to be beneath the Document constructor.
<rdar://problem/9304545>
Seem like SVG documents are leaking: 2968 WebCore::XMLDocumentParser::append(WebCore::SegmentedString const&) 340 WebCore::SVGDocument::create(WebCore::Frame*, WebCore::KURL const&
This is very likely https://bugs.webkit.org/show_bug.cgi?id=59072. We are leaking piles of SVG documents. 84151 is likely a red herring, it just made the leaks visible to the leaks checker (probably by removing a document back reference).
This seems not to be happening anymore.