I'm getting false positive leaks from Safari with ToT WebKit release build (with either FastMalloc or system allocator).
PtrAndFlags has a debug-only mechanism that makes it work with Mac OS X leaks tool. This is insufficient, because we need leaks to work in release mode, too. This is sometimes useful for WebKit development, but much more importantly, every Mac application that uses WebKit will get false positives from leaks tool.
*** This bug has been marked as a duplicate of bug 33731 ***
Duped to newer bug, filed in error, since that now has more info (i.e. patches).