Pepper: Add a C++ wrapper for the trusted file chooser.

ppapi/cpp/dev/file_chooser_dev.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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 PPAPI_CPP_DEV_FILE_CHOOSER_DEV_H_
 #define PPAPI_CPP_DEV_FILE_CHOOSER_DEV_H_
 
 #include "ppapi/c/dev/ppb_file_chooser_dev.h"
 #include "ppapi/cpp/resource.h"
 
 namespace pp {
@@ skipping 36 matching lines @@
 
   FileChooser_Dev(const FileChooser_Dev& other);
 
   /// This function displays a previously created file chooser resource as a
   /// dialog box, prompting the user to choose a file or files. The callback is
   /// called with PP_OK on successful completion with a file (or files) selected
   /// or PP_ERROR_USERCANCEL if the user selected no file.
   ///
   /// @return PP_OK_COMPLETIONPENDING if request to show the dialog was
   /// successful, another error code from pp_errors.h on failure.
-  int32_t Show(const CompletionCallback& cc);
+  virtual int32_t Show(const CompletionCallback& cc);
 
   /// After a successful completion callback call from Show, this method may be
   /// used to query the chosen files.  It should be called in a loop until it
   /// returns an is_null() FileRef.  Depending on the PP_ChooseFileMode
   /// requested when the FileChooser was created, the file refs will either
   /// be readable or writable.  Their file system type will be
   /// PP_FileSystemType_External.  If the user chose no files or cancelled the
   /// dialog, then this method will simply return an is_null() FileRef the
   /// first time it is called.
-  FileRef GetNextChosenFile() const;
+  virtual FileRef GetNextChosenFile() const;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_DEV_FILE_CHOOSER_DEV_H_