Add glue for supporting custom MIME types in DataTransfer.

webkit/glue/webclipboard_impl.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 WEBCLIPBOARD_IMPL_H_
 #define WEBCLIPBOARD_IMPL_H_
 
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebClipboard.h"
 #include "ui/base/clipboard/clipboard.h"
 
@@ skipping 19 matching lines @@
   virtual bool isFormatAvailable(Format format, Buffer buffer);
   virtual WebKit::WebVector<WebKit::WebString> readAvailableTypes(
       Buffer buffer, bool* contains_filenames);
   virtual WebKit::WebString readPlainText(Buffer buffer);
   virtual WebKit::WebString readHTML(
       Buffer buffer,
       WebKit::WebURL* source_url,
       unsigned* fragment_start,
       unsigned* fragment_end);
   virtual WebKit::WebData readImage(Buffer buffer);
+  virtual WebKit::WebString readCustomData(
+      Buffer buffer, const WebKit::WebString& type);
   virtual void writeHTML(
       const WebKit::WebString& html_text,
       const WebKit::WebURL& source_url,
       const WebKit::WebString& plain_text,
       bool write_smart_paste);
   virtual void writePlainText(const WebKit::WebString& plain_text);
   virtual void writeURL(
       const WebKit::WebURL& url,
       const WebKit::WebString& title);
   virtual void writeImage(
       const WebKit::WebImage& image,
       const WebKit::WebURL& source_url,
       const WebKit::WebString& title);
   virtual void writeDataObject(const WebKit::WebDragData& data);
 
  private:
   bool ConvertBufferType(Buffer, ui::Clipboard::Buffer*);
   ClipboardClient* client_;
 };
 
 }  // namespace webkit_glue
 
 #endif  // WEBCLIPBOARD_IMPL_H_