Add BrowserSelectFileDialogTest.OpenCloseFileDialog

ui/shell_dialogs/select_file_dialog.h

Index: ui/shell_dialogs/select_file_dialog.h
diff --git a/ui/shell_dialogs/select_file_dialog.h b/ui/shell_dialogs/select_file_dialog.h
index b5c877b541c361230604320952c5503d91382d50..0669cfa3f701b8a5fd023f0ddfee55213199f446 100644
--- a/ui/shell_dialogs/select_file_dialog.h
+++ b/ui/shell_dialogs/select_file_dialog.h
@@ -170,6 +170,10 @@ class SHELL_DIALOGS_EXPORT SelectFileDialog
                   const base::FilePath::StringType& default_extension,
                   gfx::NativeWindow owning_window,
                   void* params);
+
+  // Close the file-picker by sending an ESC key event to it.

[msw, 2015/10/23 22:33:26]

nit: technically the ESC key technique is specific to the GTK2 impl, so I'd
remove that part of this comment (or move it into the body of the gtk2 impl).

+  virtual void Close();
+
   bool HasMultipleFileTypeChoices();
 
   // Sets the global ShellDialogsDelegate. Defaults to NULL.