They are showing up in the output of a lot of layout tests (e.g. plugins/access-after-page-destroyed.html), particularly due to the call in const TextCheckerState& TextChecker::state() { notImplemented(); return textCheckerState; } We should disable the UNIMPLEMENTED warnings in TextCheckerWin.cpp.
This can be done with #define DISABLE_NOT_IMPLEMENTED_WARNINGS 1
Created attachment 79946 [details] Patch
Comment on attachment 79946 [details] Patch Committed in r76543 http://trac.webkit.org/changeset/76543