further fix for 191460, r=bzbarsky, sr=mscott, don't do forced reverse lookups on file extensions even if we have content type

mailnews/mailnews.js

@@ -193,7 +193,6 @@ pref("mailnews.offline_sync_news",         false);
 pref("mailnews.offline_sync_send_unsent",  true);
 pref("mailnews.offline_sync_work_offline", false);   
 pref("mailnews.force_ascii_search",         false);
-pref("mailnews.autolookup_unknown_mime_types",  true);
 
 pref("mailnews.send_default_charset",       "chrome://messenger/locale/messenger.properties");
 pref("mailnews.view_default_charset",       "chrome://messenger/locale/messenger.properties");

mailnews/mime/src/mimei.cpp

@@ -772,27 +772,13 @@ mime_create (const char *content_type, MimeHeaders *hdrs,
   char *content_disposition = 0;
   MimeObject *obj = 0;
   char *override_content_type = 0;
-  static PRBool reverse_lookup = PR_FALSE, got_lookup_pref = PR_FALSE;
-
-  if (!got_lookup_pref)
-  {
-     nsIPref *pref = GetPrefServiceManager(opts);   // Pref service manager 
-     if (pref)
-     {
-       pref->GetBoolPref("mailnews.autolookup_unknown_mime_types",&reverse_lookup);
-       got_lookup_pref = PR_TRUE;
-     }
-  }
 
 
   /* There are some clients send out all attachments with a content-type
 	 of application/octet-stream.  So, if we have an octet-stream attachment,
 	 try to guess what type it really is based on the file extension.  I HATE
 	 that we have to do this...
-
-     If the preference "mailnews.autolookup_unknown_mime_types" is set to PR_TRUE,
-     then we try to do this EVERY TIME when we do not have an entry for the given
-	 MIME type in our table, not only when it's application/octet-stream. */
+  */
   if (hdrs && opts && opts->file_type_fn &&
 
 	  /* ### mwelch - don't override AppleSingle */
@@ -801,13 +787,7 @@ mime_create (const char *content_type, MimeHeaders *hdrs,
 	  (content_type ? nsCRT::strcasecmp(content_type, MULTIPART_APPLEDOUBLE) : PR_TRUE) &&
 	  (!content_type ||
 	   !nsCRT::strcasecmp(content_type, APPLICATION_OCTET_STREAM) ||
-	   !nsCRT::strcasecmp(content_type, UNKNOWN_CONTENT_TYPE) ||
-	   (reverse_lookup
-#if 0
-	    && !NET_cinfo_find_info_by_type((char*)content_type))))
-#else
-        )))
-#endif
+	   !nsCRT::strcasecmp(content_type, UNKNOWN_CONTENT_TYPE)))
 	{
 	  char *name = MimeHeaders_get_name(hdrs, opts);
 	  if (name)