I noticed that our test bots were not generating crash dumps because the _NT_SYMBOL_PATH environment variable was not always properly defined on our test bots.
A better solution is to fall back to using the Microsoft Symbol Servers in this case, rather than failing to generate dump files. The only downside is some increased test latency due to having to query and download symbols (on demand) from MSDN when symbols are not available locally.
Created attachment 224411 [details]
Committed r164244: <http://trac.webkit.org/changeset/164244>
Fixed webkitpy tests on Mac in http://trac.webkit.org/changeset/164247.