prune down content_dll change to just the CONTENT_EXPORTS

ui/base/dragdrop/download_file_interface.h

 // 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 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/memory/ref_counted.h"
 
+#include "ui/base/ui_export.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
+class UI_EXPORT 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
+class UI_EXPORT 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() {}
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_DRAGDROP_DOWNLOAD_FILE_INTERFACE_H_