Coverity: Fix several pass-by-values.

content/browser/webui/web_ui_message_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 "content/public/browser/web_ui_message_handler.h"
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "googleurl/src/gurl.h"
 
 namespace content {
 
 void WebUIMessageHandler::SetURLAndTitle(DictionaryValue* dictionary,
-                                         string16 title,
+                                         const string16& title,
                                          const GURL& gurl) {
   dictionary->SetString("url", gurl.spec());
 
   bool using_url_as_the_title = false;
+  string16 title_to_set(title);
   if (title.empty()) {
     using_url_as_the_title = true;
-    title = UTF8ToUTF16(gurl.spec());
+    title_to_set = UTF8ToUTF16(gurl.spec());
   }
 
   // Since the title can contain BiDi text, we need to mark the text as either
   // RTL or LTR, depending on the characters in the string. If we use the URL
   // as the title, we mark the title as LTR since URLs are always treated as
   // left to right strings.
-  string16 title_to_set(title);
   if (base::i18n::IsRTL()) {
     if (using_url_as_the_title) {
       base::i18n::WrapStringWithLTRFormatting(&title_to_set);
     } else {
       base::i18n::AdjustStringForLocaleDirection(&title_to_set);
     }
   }
   dictionary->SetString("title", title_to_set);
 }
 
@@ skipping 24 matching lines @@
 
 string16 WebUIMessageHandler::ExtractStringValue(const ListValue* value) {
   string16 string16_value;
   if (value->GetString(0, &string16_value))
     return string16_value;
   NOTREACHED();
   return string16();
 }
 
 }  // namespace content