Add glue for supporting custom MIME types in DataTransfer.

webkit/glue/clipboard_client.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 WEBKIT_GLUE_CLIPBOARD_CLIENT_H_
 #define WEBKIT_GLUE_CLIPBOARD_CLIENT_H_
 
 #include "ui/base/clipboard/clipboard.h"
 
 class GURL;
@@ skipping 41 matching lines @@
                              std::string* result) = 0;
 
   // Reads HTML from the clipboard, if available.
   virtual void ReadHTML(ui::Clipboard::Buffer buffer, string16* markup,
                         GURL* url, uint32* fragment_start,
                         uint32* fragment_end) = 0;
 
   // Reads and image from the clipboard, if available.
   virtual void ReadImage(ui::Clipboard::Buffer buffer, std::string* data) = 0;
 
+  // Reads a custom data type from the clipboard, if available.
+  virtual void ReadCustomData(ui::Clipboard::Buffer buffer,
+                              const string16& type,
+                              string16* data) = 0;
+
   // Creates a context to write clipboard data. May return NULL.
   virtual WriteContext* CreateWriteContext() = 0;
 };
 
 }  // namespace webkit_glue
 
 #endif  // WEBKIT_GLUE_CLIPBOARD_CLIENT_H_