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

ios/chrome/browser/history/web_history_service_factory.cc

 // Copyright 2015 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 "ios/chrome/browser/history/web_history_service_factory.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include "components/browser_sync/browser/profile_sync_service.h"
 #include "components/history/core/browser/web_history_service.h"
@@ skipping 49 matching lines @@
   DependsOn(ios::SigninManagerFactory::GetInstance());
 }
 
 WebHistoryServiceFactory::~WebHistoryServiceFactory() {
 }
 
 std::unique_ptr<KeyedService> WebHistoryServiceFactory::BuildServiceInstanceFor(
     web::BrowserState* context) const {
   ios::ChromeBrowserState* browser_state =
       ios::ChromeBrowserState::FromBrowserState(context);
-  return base::WrapUnique(new history::WebHistoryService(
+  return base::MakeUnique<history::WebHistoryService>(
       OAuth2TokenServiceFactory::GetForBrowserState(browser_state),
       ios::SigninManagerFactory::GetForBrowserState(browser_state),
-      browser_state->GetRequestContext()));
+      browser_state->GetRequestContext());
 }
 
 }  // namespace ios