Move more dnd related files to ui/base

ui/base/dragdrop/download_file_interface.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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 APP_DOWNLOAD_FILE_INTERFACE_H_
-#define APP_DOWNLOAD_FILE_INTERFACE_H_
+#ifndef UI_BASE_DRAGDROP_DOWNLOAD_FILE_INTERFACE_H_
+#define UI_BASE_DRAGDROP_DOWNLOAD_FILE_INTERFACE_H_
 #pragma once
 
 #include "build/build_config.h"
 
 #include "base/basictypes.h"
 #include "base/ref_counted.h"
 
 #if defined(OS_WIN)
 #include <objidl.h>
 #endif
 
 class FilePath;
 
+namespace ui {
+
 // Defines the interface to observe the status of file download.
 class DownloadFileObserver
     : public base::RefCountedThreadSafe<DownloadFileObserver> {
  public:
   virtual void OnDownloadCompleted(const FilePath& file_path) = 0;
   virtual void OnDownloadAborted() = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<DownloadFileObserver>;
   virtual ~DownloadFileObserver() {}
 };
 
 // Defines the interface to control how a file is downloaded.
 class DownloadFileProvider
     : public base::RefCountedThreadSafe<DownloadFileProvider> {
  public:
   virtual bool Start(DownloadFileObserver* observer) = 0;
   virtual void Stop() = 0;
 #if defined(OS_WIN)
   virtual IStream* GetStream() = 0;
 #endif
 
  protected:
   friend class base::RefCountedThreadSafe<DownloadFileProvider>;
   virtual ~DownloadFileProvider() {}
 };
 
-#endif  // APP_DOWNLOAD_FILE_INTERFACE_H_
+}  // namespace ui
+
+#endif  // UI_BASE_DRAGDROP_DOWNLOAD_FILE_INTERFACE_H_