[Coverity] CID 6203: pass std::string by const-ref

chrome/browser/character_encoding.cc

 // Copyright (c) 2011 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/character_encoding.h"
 
 #include <map>
 #include <set>
 
 #include "base/logging.h"
@@ skipping 236 matching lines @@
         tokenizer.token());
     // Ignore invalid encoding.
     if (!id)
       continue;
     available_list->push_back(id);
     if (available_list->size() == maximum_size)
       return;
   }
 }
 
-string16 GetEncodingDisplayName(std::string encoding_name,
+string16 GetEncodingDisplayName(const std::string& encoding_name,
                                 int category_string_id) {
   string16 category_name = l10n_util::GetStringUTF16(category_string_id);
   if (category_string_id != IDS_ENCODING_KOREAN &&
       category_string_id != IDS_ENCODING_THAI &&
       category_string_id != IDS_ENCODING_TURKISH) {
     const CanonicalNameDisplayNameMapType* map =
         CanonicalEncodingMapSingleton()->GetCanonicalNameDisplayNameMapData();
     DCHECK(map);
 
     CanonicalNameDisplayNameMapType::const_iterator found_name =
@@ skipping 269 matching lines @@
   // Insert new encoding to head of selected encoding list.
   *selected_encodings = encoding_name;
   // Generate the string for rest selected encoding list.
   for (std::vector<int>::const_iterator it = selected_encoding_list.begin();
        it != selected_encoding_list.end(); ++it) {
     selected_encodings->append(1, L',');
     selected_encodings->append(GetCanonicalEncodingNameByCommandId(*it));
   }
   return true;
 }