Cleanup: Make ExtensionIconSet::Get return a const std::string& rather than a

extensions/common/manifest_handlers/icons_handler.cc

 // Copyright 2014 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 "extensions/common/manifest_handlers/icons_handler.h"
 
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 19 matching lines @@
   IconsInfo* info = static_cast<IconsInfo*>(
       extension->GetManifestData(keys::kIcons));
   return info ? info->icons : g_empty_icon_set.Get();
 }
 
 // static
 ExtensionResource IconsInfo::GetIconResource(
     const Extension* extension,
     int size,
     ExtensionIconSet::MatchType match_type) {
-  std::string path = GetIcons(extension).Get(size, match_type);
+  const std::string& path = GetIcons(extension).Get(size, match_type);
   return path.empty() ? ExtensionResource() : extension->GetResource(path);
 }
 
 // static
 GURL IconsInfo::GetIconURL(const Extension* extension,
                            int size,
                            ExtensionIconSet::MatchType match_type) {
-  std::string path = GetIcons(extension).Get(size, match_type);
+  const std::string& path = GetIcons(extension).Get(size, match_type);
   return path.empty() ? GURL() : extension->GetResourceURL(path);
 }
 
 IconsHandler::IconsHandler() {
 }
 
 IconsHandler::~IconsHandler() {
 }
 
 bool IconsHandler::Parse(Extension* extension, base::string16* error) {
@@ skipping 24 matching lines @@
                                              extension,
                                              IDS_EXTENSION_LOAD_ICON_FAILED,
                                              error);
 }
 
 const std::vector<std::string> IconsHandler::Keys() const {
   return SingleKey(keys::kIcons);
 }
 
 }  // namespace extensions