To see the leaks:
1. Go to http://build.webkit.org/LeaksViewer/?url=%2Fresults%2FLion%20Intel%20Leaks%2Fr100768%20%28193%29%2F
2. Dig into malloc_zone_malloc > malloc > WTF::fastMalloc
Many of the leaks in that node are (indirect) callees of RenderSVGShadowTreeRootContainer::updateFromElement.
We thought we fixed these in bug 56672, but either we were wrong or they got reintroduced.