Bug 1585366 - Remove a gcc mangling workaround for Windows r=dmajor

Bug 1329593 introduced this for the mingw-gcc build; but we no longer support this
build and mingw-clang does not need it.

Differential Revision: https://phabricator.services.mozilla.com/D48606

--HG--
extra : moz-landing-system : lando

toolkit/components/url-classifier/nsUrlClassifierDBService.h

@@ -26,13 +26,6 @@
 #include "LookupCache.h"
 #include "HashStore.h"
 
-// GCC < 6.1 workaround, see bug 1329593
-#if defined(XP_WIN) && defined(__MINGW32__)
-#  define GCC_MANGLING_WORKAROUND __stdcall
-#else
-#  define GCC_MANGLING_WORKAROUND
-#endif
-
 // The hash length for a domain key.
 #define DOMAIN_LENGTH 4
 
@@ -180,12 +173,12 @@ class nsUrlClassifierDBServiceWorker final : public nsIUrlClassifierDBService {
       LookupResultArray& aResults);
 
   // Open the DB connection
-  nsresult GCC_MANGLING_WORKAROUND OpenDb();
+  nsresult OpenDb();
 
   // Provide a way to forcibly close the db connection.
-  nsresult GCC_MANGLING_WORKAROUND CloseDb();
+  nsresult CloseDb();
 
-  nsresult GCC_MANGLING_WORKAROUND PreShutdown();
+  nsresult PreShutdown();
 
   nsresult CacheCompletions(const ConstCacheResultArray& aEntries);