Create DOMWindowStorage as a DOMWindowLifecycleObserver

Source/core/storage/DOMWindowStorage.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 "config.h"
+#include "core/storage/DOMWindowStorage.h"
+
+#include "core/dom/Document.h"
+#include "core/events/Event.h"
+#include "core/frame/LocalDOMWindow.h"
+#include "core/page/Page.h"
+
+namespace blink {
+
+DOMWindowStorage::DOMWindowStorage(Document& document)
+    : DOMWindowLifecycleObserver(document.domWindow())
+    , m_document(document)
+{
+}
+
+DOMWindowStorage::~DOMWindowStorage()
+{
+}
+
+// static
+const char* DOMWindowStorage::supplementName()
+{
+    return "DOMWindowStorage";
+}
+
+// static
+DOMWindowStorage& DOMWindowStorage::from(Document& document)
+{
+    DOMWindowStorage* controller = static_cast<DOMWindowStorage*>(WillBeHeapSupplement<Document>::from(document, supplementName()));

[michaeln, 2014/12/16 00:12:11]

I'm not familiar with how 'supplements' are typically named in blink maybe the
pattern you've used is common, in which case never mind my naming nit comment.

Grokking what this new class is isn't obvious at a glance, maybe call it
DOMWindowStorageSupplement?

+    if (!controller) {
+        controller = new DOMWindowStorage(document);
+        DocumentSupplement::provideTo(document, supplementName(), adoptPtrWillBeNoop(controller));
+    }
+    return *controller;
+}
+
+void DOMWindowStorage::didAddEventListener(LocalDOMWindow* window, const AtomicString& eventType)
+{
+    if (eventType == EventTypeNames::storage) {
+        // 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.
+        window->localStorage(IGNORE_EXCEPTION);
+        window->sessionStorage(IGNORE_EXCEPTION);
+    }
+}
+
+} // namespace blink