Add first-class support for user scripts

chrome/common/extensions/extension_error_utils.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/common/extensions/extension_error_utils.h"
 
 #include "base/string_util.h"
 
 std::string ExtensionErrorUtils::FormatErrorMessage(
     const std::string& format,
-    const std::string s1) {
+    const std::string& s1) {
   std::string ret_val = format;
   ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s1);
   return ret_val;
 }
 
 std::string ExtensionErrorUtils::FormatErrorMessage(
     const std::string& format,
-    const std::string s1,
-    const std::string s2) {
+    const std::string& s1,
+    const std::string& s2) {
   std::string ret_val = format;
   ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s1);
   ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s2);
   return ret_val;
 }
+
+std::string ExtensionErrorUtils::FormatErrorMessage(
+    const std::string& format,
+    const std::string& s1,
+    const std::string& s2,
+    const std::string& s3) {
+  std::string ret_val = format;
+  ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s1);
+  ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s2);
+  ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s3);
+  return ret_val;
+}