Cleanup: Pass std::string as const reference if possible

chrome/browser/ui/webui/ntp/new_tab_page_sync_handler.cc

 // Copyright (c) 2012 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/browser/ui/webui/ntp/new_tab_page_sync_handler.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 144 matching lines @@
   BuildAndSendSyncStatus();
 }
 
 void NewTabPageSyncHandler::OnSigninAllowedPrefChange() {
   // Don't do anything if the page has not yet loaded.
   if (waiting_for_initial_page_load_)
     return;
   BuildAndSendSyncStatus();
 }
 
-void NewTabPageSyncHandler::SendSyncMessageToPage(
-    MessageType type, std::string msg,
-    std::string linktext) {
+void NewTabPageSyncHandler::SendSyncMessageToPage(MessageType type,
+                                                  const std::string& msg,
+                                                  const std::string& linktext) {
   base::DictionaryValue value;
   std::string user;
   std::string title;
   std::string linkurl;
 
   // If there is nothing to show, we should hide the sync section altogether.
   if (type == HIDE || (msg.empty() && linktext.empty())) {
     value.SetBoolean("syncsectionisvisible", false);
   } else {
     if (type == SYNC_ERROR)
@@ skipping 19 matching lines @@
       if (linkurl.empty()) {
         value.SetBoolean("linkurlisset", false);
       } else {
         value.SetBoolean("linkurlisset", true);
         value.SetString("linkurl", linkurl);
       }
     }
   }
   web_ui()->CallJavascriptFunction("ntp.syncMessageChanged", value);
 }