ui/shell_dialogs: Use base::string16 now that string16 was moved into base namespace.

ui/shell_dialogs/gtk/select_file_dialog_impl_gtk.cc

Index: ui/shell_dialogs/gtk/select_file_dialog_impl_gtk.cc
diff --git a/ui/shell_dialogs/gtk/select_file_dialog_impl_gtk.cc b/ui/shell_dialogs/gtk/select_file_dialog_impl_gtk.cc
index c47ad0bec68e79f3d5cf3c16ff67db8863c215d1..6f07befbe7678686d90edd12d20c0ba53d7ceb96 100644
--- a/ui/shell_dialogs/gtk/select_file_dialog_impl_gtk.cc
+++ b/ui/shell_dialogs/gtk/select_file_dialog_impl_gtk.cc
@@ -49,7 +49,7 @@ class SelectFileDialogImplGTK : public ui::SelectFileDialogImpl {
   // |params| is user data we pass back via the Listener interface.
   virtual void SelectFileImpl(
       Type type,
-      const string16& title,
+      const base::string16& title,
       const base::FilePath& default_path,
       const FileTypeInfo* file_types,
       int file_type_index,
@@ -166,7 +166,7 @@ bool SelectFileDialogImplGTK::HasMultipleFileTypeChoicesImpl() {
 // We ignore |default_extension|.
 void SelectFileDialogImplGTK::SelectFileImpl(
     Type type,
-    const string16& title,
+    const base::string16& title,
     const base::FilePath& default_path,
     const FileTypeInfo* file_types,
     int file_type_index,