Make the file chooser use PP_ArrayOutput

ppapi/cpp/trusted/file_chooser_trusted.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 PPAPI_CPP_TRUSTED_FILE_CHOOSER_TRUSTED_H_
 #define PPAPI_CPP_TRUSTED_FILE_CHOOSER_TRUSTED_H_
 
 #include <string>
 
 #include "ppapi/cpp/dev/file_chooser_dev.h"
@@ skipping 10 matching lines @@
                       const Var& accept_mime_types,
                       bool save_as,
                       const std::string& suggested_file_name);
 
   FileChooser_Trusted(const FileChooser_Trusted& other);
 
   FileChooser_Trusted& operator=(const FileChooser_Trusted& other);
 
   // Overrides of method in superclass. This shows without requiring a user
   // gesture (and can also show save dialogs).
-  virtual int32_t Show(const CompletionCallback& cc);
+  virtual int32_t Show(
+      const CompletionCallbackWithOutput< std::vector<FileRef> >& callback);
 
  private:
   bool save_as_;
   std::string suggested_file_name_;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_TRUSTED_FILE_CHOOSER_TRUSTED_H_