Get drag and drop working for win aura.

ui/base/dragdrop/os_exchange_data_provider_win.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 UI_BASE_DRAGDROP_OS_EXCHANGE_DATA_PROVIDER_WIN_H_
 #define UI_BASE_DRAGDROP_OS_EXCHANGE_DATA_PROVIDER_WIN_H_
 
 #include <objidl.h>
 #include <shlobj.h>
 #include <string>
@@ skipping 143 matching lines @@
   virtual ~OSExchangeDataProviderWin();
 
   IDataObject* data_object() const { return data_.get(); }
   IDataObjectAsyncCapability* async_operation() const { return data_.get(); }
 
   // OSExchangeData::Provider methods.
   virtual void SetString(const string16& data);
   virtual void SetURL(const GURL& url, const string16& title);
   virtual void SetFilename(const FilePath& path);
   virtual void SetFilenames(
-      const std::vector<OSExchangeData::FileInfo>& filenames) {
-    NOTREACHED();
-  }
+      const std::vector<OSExchangeData::FileInfo>& filenames);
   virtual void SetPickledData(OSExchangeData::CustomFormat format,
                               const Pickle& data);
   virtual void SetFileContents(const FilePath& filename,
                                const std::string& file_contents);
   virtual void SetHtml(const string16& html, const GURL& base_url);
 
   virtual bool GetString(string16* data) const;
   virtual bool GetURLAndTitle(GURL* url, string16* title) const;
   virtual bool GetFilename(FilePath* path) const;
   virtual bool GetFilenames(
-      std::vector<OSExchangeData::FileInfo>* filenames) const {
-    NOTREACHED();
-    return false;
-  }
+      std::vector<OSExchangeData::FileInfo>* filenames) const;
   virtual bool GetPickledData(OSExchangeData::CustomFormat format,
                               Pickle* data) const;
   virtual bool GetFileContents(FilePath* filename,
                                std::string* file_contents) const;
   virtual bool GetHtml(string16* html, GURL* base_url) const;
   virtual bool HasString() const;
   virtual bool HasURL() const;
   virtual bool HasFile() const;
   virtual bool HasFileContents() const;
   virtual bool HasHtml() const;
   virtual bool HasCustomFormat(OSExchangeData::CustomFormat format) const;
   virtual void SetDownloadFileInfo(
       const OSExchangeData::DownloadFileInfo& download_info);
 
  private:
   scoped_refptr<DataObjectImpl> data_;
   base::win::ScopedComPtr<IDataObject> source_object_;
 
   DISALLOW_COPY_AND_ASSIGN(OSExchangeDataProviderWin);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_DRAGDROP_OS_EXCHANGE_DATA_PROVIDER_WIN_H_