IndexedDB: Replace 0 with nullptr where appropriate

Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp

Index: Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp
diff --git a/Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp b/Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp
index e667158e9ebd8d80855013357ca2efe1c02d301d..905a8a0f4651610dcaa4347536ba673fe5c4e9a7 100644
--- a/Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp
+++ b/Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp
@@ -84,14 +84,14 @@ IDBFactory* DOMWindowIndexedDatabase::indexedDB()
 {
     Document* document = m_window.document();
     if (!document)
-        return 0;
+        return nullptr;
 
     Page* page = document->page();
     if (!page)
-        return 0;
+        return nullptr;
 
     if (!m_window.isCurrentlyDisplayedInFrame())
-        return 0;
+        return nullptr;
 
     if (!m_idbFactory)
         m_idbFactory = IDBFactory::create(IndexedDBClient::create());