better error handling from IC, if we can't load the homepage, use about:blank

(bug 245359)

camino/src/preferences/PreferenceManager.mm

@@ -653,8 +653,12 @@ static void SCProxiesChangedCallback(SCDynamicStoreRef store, CFArrayRef changed
   if (NS_FAILED(rv) || mode == 1) {
     // see which home page to use
     PRBool boolPref;
-    if (NS_SUCCEEDED(mPrefs->GetBoolPref("chimera.use_system_home_page", &boolPref)) && boolPref)
-      return [self getICStringPref:kICWWWHomePage];
+    if (NS_SUCCEEDED(mPrefs->GetBoolPref("chimera.use_system_home_page", &boolPref)) && boolPref) {
+      NSString* homePage = [self getICStringPref:kICWWWHomePage];
+      if (!homePage)
+        homePage = @"about:blank";
+      return homePage;
+    }
 
     nsCOMPtr<nsIPrefBranch> prefBranch = do_QueryInterface(mPrefs);
     if (!prefBranch) return @"about:blank";