RFR: 8236651: Simplify and update glass gtk backend

[Pankaj Bansal]

On Sun, 14 Jun 2020 06:49:42 GMT, Pankaj Bansal <pbansal at openjdk.org> wrote:

>> I have investigated the Tab Pane Drag Test and it works manually.
>> 
>> import javafx.application.Application;
>> import javafx.scene.Scene;
>> import javafx.scene.control.Tab;
>> import javafx.scene.control.TabPane;
>> import javafx.stage.Stage;
>> 
>> public class Test
>>         extends Application {
>> 
>>     @Override
>>     public void start(Stage stage) {
>>         TabPane tabPane = new TabPane();
>>         tabPane.setTabDragPolicy(TabPane.TabDragPolicy.REORDER);
>>         Scene scene = new Scene(tabPane, 800, 600);
>>         stage.setScene(scene);
>>         Tab tab1 = new Tab("Tab1");
>>         Tab tab2 = new Tab("Tab2");
>> 
>>         tabPane.getTabs().addAll(tab1, tab2);
>> 
>> 
>>         stage.setAlwaysOnTop(true);
>>         stage.show();
>>     }
>> 
>>     public static class Main {
>>         public static void main(String[] args) {
>>             Application.launch(Test.class, args);
>>         }
>>     }
>> }
>> 
>> It also works if I switch back to GDK Events instead of Gtk Signals. But it is a drag test, by experience they don't
>> work well on Robot.
>
> Following are results in Ubuntu 18.04 after fix for tab pane tests.
> <img width="516" alt="Results_18 04"
> src="https://user-images.githubusercontent.com/6153953/84587007-3abc2880-ae39-11ea-8b61-0cbb86e4d4b5.png">

This is the result on OL 82 with latest commit
<img width="596" alt="OL82"
src="https://user-images.githubusercontent.com/6153953/84592508-d82c5200-ae63-11ea-87d3-7f55671ed302.png">

-------------

PR: https://git.openjdk.java.net/jfx/pull/77