Revert of Move JoinString to the base namespace

chrome/browser/ui/libgtk2ui/select_file_dialog_impl_gtk2.cc

 // 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.
 
 #include <gtk/gtk.h>
 #include <map>
 #include <set>
 #include <vector>
 
 // Xlib defines RootWindow
@@ skipping 301 matching lines @@
     // The description vector may be blank, in which case we are supposed to
     // use some sort of default description based on the filter.
     if (i < file_types_.extension_description_overrides.size()) {
       gtk_file_filter_set_name(filter, base::UTF16ToUTF8(
           file_types_.extension_description_overrides[i]).c_str());
     } else {
       // There is no system default filter description so we use
       // the extensions themselves if the description is blank.
       std::vector<std::string> fallback_labels_vector(fallback_labels.begin(),
                                                       fallback_labels.end());
-      std::string fallback_label =
-          base::JoinString(fallback_labels_vector, ",");
+      std::string fallback_label = JoinString(fallback_labels_vector, ',');
       gtk_file_filter_set_name(filter, fallback_label.c_str());
     }
 
     gtk_file_chooser_add_filter(chooser, filter);
     if (i == file_type_index_ - 1)
       gtk_file_chooser_set_filter(chooser, filter);
   }
 
   // Add the *.* filter, but only if we have added other filters (otherwise it
   // is implied).
@@ skipping 294 matching lines @@
   g_free(filename);
   if (pixbuf) {
     gtk_image_set_from_pixbuf(GTK_IMAGE(preview_), pixbuf);
     g_object_unref(pixbuf);
   }
   gtk_file_chooser_set_preview_widget_active(GTK_FILE_CHOOSER(chooser),
                                              pixbuf ? TRUE : FALSE);
 }
 
 }  // namespace libgtk2ui