RFR: JDK-8291823: IGV: Fix "Save selected groups"

[Roberto Castañeda Lozano]

On Wed, 3 Aug 2022 15:31:51 GMT, Tobias Holenstein <tholenstein at openjdk.org> wrote:

> In IGV the button `Save selected groups to XML file...` is broken and never activated. 
> 
> *Before this fix* 
> Bellow you can see the Outline with two selected groups, but the `Save selected groups to XML file...` button does not work:
> <img width="307" alt="before_groups_selected" src="https://user-images.githubusercontent.com/71546117/182790122-ed272ed4-1cca-4d5c-ae2a-6c2f44fd3565.png">
> 
> *After this fix* 
> Now the `Save selected groups to XML file...` button works if at least one groups is selected:
> <img width="273" alt="groups_selected" src="https://user-images.githubusercontent.com/71546117/182790406-08d6366a-4351-49d4-959e-79948bc4984d.png">
> 
> 
> *After this fix* 
> The `Save selected groups to XML file...` button is greyed out if no groups are selected:
> <img width="272" alt="no_groups_selected" src="https://user-images.githubusercontent.com/71546117/182792546-ef5169a8-d4d8-4981-aee1-af7e30895925.png">
> 
> 
> 
> 
> *Before this fix* 
> The `Save all groups to XML` and the `Remove all graphs and groups` buttons where available even if no graphs or groups were loaded:
> <img width="306" alt="before_no_groups" src="https://user-images.githubusercontent.com/71546117/182791984-dbec8829-fd81-4ce8-aa05-2d2030f89bd3.png">
> 
> *After this fix* 
> The `Save all groups to XML` and the `Remove all graphs and groups` buttons are greyed out if no graphs or groups are loaded:
> <img width="271" alt="no_groups" src="https://user-images.githubusercontent.com/71546117/182792159-88b0fa32-89dd-4e02-a3a9-66bdc77ecf70.png">

Thanks for working on this @tobiasholenstein!

I tested the changeset manually and found that, after selecting all groups listed in the Outline window and clicking on `Remove selected graphs and groups`, we end up with an empty outline where the `Save selected groups to XML file...` and `Remove selected graphs and groups` buttons are still enabled:

![empty-outline](https://user-images.githubusercontent.com/8792647/182801237-2a8d76f3-34dd-4714-a6f9-c5164ad459c7.png)

Nit: to ease reviewing (and backporting, etc.), try to minimize the number of empty lines added/removed that are not directly related to the changeset.

src/utils/IdealGraphVisualizer/Coordinator/src/main/java/com/sun/hotspot/igv/coordinator/actions/ImportAction.java line 2:

> 1: /*
> 2:  * Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.

Please do not update the copyright line if there are no other changes in the file.

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

Changes requested by rcastanedalo (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9730