Move nullable_string16.h to the string subdirectory.

content/browser/dom_storage/dom_storage_message_filter.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_MESSAGE_FILTER_H_
 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_MESSAGE_FILTER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/public/browser/browser_message_filter.h"
 #include "webkit/browser/dom_storage/dom_storage_context.h"
 #include "webkit/common/dom_storage/dom_storage_types.h"
 
 class GURL;
+
+namespace base {
 class NullableString16;
+}
 
 namespace dom_storage {
 class DomStorageArea;
 class DomStorageContext;
 class DomStorageHost;
 }
 
 namespace content {
 class DOMStorageContextImpl;
 
@@ skipping 30 matching lines @@
                     const GURL& page_url);
   void OnClear(int connection_id, const GURL& page_url);
   void OnFlushMessages();
 
   // DomStorageContext::EventObserver implementation which
   // sends events back to our renderer process.
   virtual void OnDomStorageItemSet(
       const dom_storage::DomStorageArea* area,
       const string16& key,
       const string16& new_value,
-      const NullableString16& old_value,
+      const base::NullableString16& old_value,
       const GURL& page_url) OVERRIDE;
   virtual void OnDomStorageItemRemoved(
       const dom_storage::DomStorageArea* area,
       const string16& key,
       const string16& old_value,
       const GURL& page_url) OVERRIDE;
   virtual void OnDomStorageAreaCleared(
       const dom_storage::DomStorageArea* area,
       const GURL& page_url) OVERRIDE;
 
   void SendDomStorageEvent(
       const dom_storage::DomStorageArea* area,
       const GURL& page_url,
-      const NullableString16& key,
-      const NullableString16& new_value,
-      const NullableString16& old_value);
+      const base::NullableString16& key,
+      const base::NullableString16& new_value,
+      const base::NullableString16& old_value);
 
   scoped_refptr<dom_storage::DomStorageContext> context_;
   scoped_ptr<dom_storage::DomStorageHost> host_;
   int connection_dispatching_message_for_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(DOMStorageMessageFilter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_MESSAGE_FILTER_H_