Use a new Supplement constructor for Supplement<Document> (Part 1)

third_party/WebKit/Source/modules/storage/DOMWindowStorageController.cpp

 // 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 "modules/storage/DOMWindowStorageController.h"
 
 #include "core/dom/Document.h"
 #include "core/events/Event.h"
 #include "core/page/Page.h"
 #include "modules/storage/DOMWindowStorage.h"
 
 namespace blink {
 
 DOMWindowStorageController::DOMWindowStorageController(Document& document)
-    : m_document(document) {
+    : Supplement<Document>(document) {
   document.domWindow()->registerEventListenerObserver(this);
 }
 
 DEFINE_TRACE(DOMWindowStorageController) {
-  visitor->trace(m_document);
   Supplement<Document>::trace(visitor);
 }
 
 // static
 const char* DOMWindowStorageController::supplementName() {
   return "DOMWindowStorageController";
 }
 
 // static
 DOMWindowStorageController& DOMWindowStorageController::from(
@@ skipping 15 matching lines @@
     // Creating these blink::Storage objects informs the system that we'd like
     // to receive notifications about storage events that might be triggered in
     // other processes. Rather than subscribe to these notifications explicitly,
     // we subscribe to them implicitly to simplify the work done by the system.
     DOMWindowStorage::from(*window).localStorage(IGNORE_EXCEPTION);
     DOMWindowStorage::from(*window).sessionStorage(IGNORE_EXCEPTION);
   }
 }
 
 }  // namespace blink