Re-write many calls to WrapUnique() with MakeUnique()

components/search_engines/default_search_policy_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 "components/search_engines/default_search_policy_handler.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 351 matching lines @@
   if (!prefs->GetString(path, &value))
     prefs->SetString(path, value);
 }
 
 void DefaultSearchPolicyHandler::EnsureListPrefExists(
     PrefValueMap* prefs,
     const std::string& path) {
   base::Value* value;
   base::ListValue* list_value;
   if (!prefs->GetValue(path, &value) || !value->GetAsList(&list_value))
-    prefs->SetValue(path, base::WrapUnique(new base::ListValue()));
+    prefs->SetValue(path, base::MakeUnique<base::ListValue>());
 }
 
 }  // namespace policy