Changes

[http://valgrind.org/ Valgrind] is a free tool for Linux and Mac that detects various kinds of memory-related errors at runtime, including leaks. Valgrind is used as part of Mozilla's continuous integration testing, though the coverage isn't great because Valgrind is slow. ==== LSAN ====[https://code.google.com/p/address-sanitizer/wiki/LeakSanitizer LeakSanitizer] (a.k.a. LSAN) is similar to Valgrind, but it runs faster because it uses static source code instrumentation. LSAN is part of Mozilla's continuous integration testing, with most tests running through it as part of the AddressSanitizer (a.k.a. ASAN) test jobs.