Bug #312940 --> instead of using an ifdef, hijack the preview text pref to allow devs

with release builds to try out the new alert prototype.

mailnews/base/src/nsMessengerWinIntegration.cpp

@@ -466,7 +466,16 @@ nsresult nsMessengerWinIntegration::ShowAlertMessage(const PRUnichar * aAlertTit
   
   if (showAlert)
   {
-#if 0
+#ifdef MOZ_THUNDERBIRD
+    // Since the new mail notification alert isn't ready for primetype yet,
+    // tie it to the showPreviewText pref so testers can try it out
+    // in their builds...
+    PRBool useNewAlert = PR_FALSE;
+    if (prefBranch)
+      prefBranch->GetBoolPref("mail.showPreviewText", &useNewAlert);
+
+    if (useNewAlert)
+    { 
       nsCOMPtr<nsISupportsArray> argsArray;
       rv = NS_NewISupportsArray(getter_AddRefs(argsArray));
       NS_ENSURE_SUCCESS(rv, rv);
@@ -491,6 +500,19 @@ nsresult nsMessengerWinIntegration::ShowAlertMessage(const PRUnichar * aAlertTit
                   "chrome,dialog=yes,titlebar=no,popup=yes", argsArray,
                    getter_AddRefs(newWindow));
      mAlertInProgress = PR_TRUE;
+    }
+    else
+    {
+      // this code will go away when the new alert service is ready to be turned on...
+      nsCOMPtr<nsIAlertsService> alertsService (do_GetService(NS_ALERTSERVICE_CONTRACTID, &rv));
+      if (NS_SUCCEEDED(rv))
+      {
+        rv = alertsService->ShowAlertNotification(NS_LITERAL_STRING(NEW_MAIL_ALERT_ICON), nsDependentString(aAlertTitle),
+                                                  nsDependentString(aAlertText), PR_TRUE, 
+                                                  NS_ConvertASCIItoUCS2(aFolderURI), this); 
+        mAlertInProgress = PR_TRUE;
+      }
+    }
 #else
     nsCOMPtr<nsIAlertsService> alertsService (do_GetService(NS_ALERTSERVICE_CONTRACTID, &rv));
     if (NS_SUCCEEDED(rv))