Fix UITest

It needs to wait until vnd.sun.star.findbar:FocusToFindbar does its
magic, which was racing with Python executing its typing.

This adds "SelectedText" property to ComboBoxUIObject::get_state.

Change-Id: I30faab2cc36a3cde59cf72ae5a383738a3ad4738
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/116694
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Tested-by: Jenkins

sw/qa/uitest/findBar/tdf136941.py

@@ -40,6 +40,9 @@ class tdf136941(UITestCase):
         self.xUITest.executeCommand("vnd.sun.star.findbar:FocusToFindbar")
 
         xfind = xWriterDoc.getChild("find")
+        self.ui_test.wait_until_property_is_updated(xfind, 'SelectedText', "Hello")
+        self.assertEqual("Hello", get_state_as_dict(xfind)['SelectedText'])
+
         xfind.executeAction("TYPE", mkPropertyValues({"TEXT": "World"}))
 
         # Without the fix in place, this test would have failed with

vcl/source/uitest/uiobject.cxx

@@ -1176,6 +1176,7 @@ void ComboBoxUIObject::execute(const OUString& rAction,
 StringMap ComboBoxUIObject::get_state()
 {
     StringMap aMap = WindowUIObject::get_state();
+    aMap["SelectedText"] = mxComboBox->GetSelected();
     return aMap;
 }