prune down content_dll change to just the CONTENT_EXPORTS

ui/base/dragdrop/download_file_interface.h

Index: ui/base/dragdrop/download_file_interface.h
diff --git a/ui/base/dragdrop/download_file_interface.h b/ui/base/dragdrop/download_file_interface.h
index ab09afd5fe8e81d6f4f10056606b2e6efaedbbd9..5b985102a26560690ee84f6e6014ba1ea817da4a 100644
--- a/ui/base/dragdrop/download_file_interface.h
+++ b/ui/base/dragdrop/download_file_interface.h
@@ -11,6 +11,8 @@
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 
+#include "ui/base/ui_export.h"
+
 #if defined(OS_WIN)
 #include <objidl.h>
 #endif
@@ -20,7 +22,7 @@ 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;
@@ -32,7 +34,7 @@ class 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;