RFR: JDK-8295934: IGV: keep node selection when changing view or graph [v3]

[Tobias Holenstein]

> In IGV nodes can be selected by clicking on it. When a user selects nodes in a certain view, e.g. "Cluster nodes into blocks" view, and then change to e.g. "Sea of nodes" view, the selection should be kept. Same when the user goes a different graph in the same group, the selection should be kept (as long as the nodes are still present)
> 
> New selection features:
> - When opening a new graph and no nodes where selected previously the root nodes is selected and centered. 
> <img width="807" alt="selected_root" src="https://user-images.githubusercontent.com/71546117/201100062-3e5cb919-cce1-41d9-8041-08a5f1c31f22.png">
> 
> - When a graph in the same group is opened, the previously selected nodes as selected as well if they are present in the graph. The selected nodes are centered in the new graph. 
> - The selected nodes are kept when changing the view, or the properties of the view (e.g. "show neighboring nodes semi-transparent") 
> <img width="370" alt="cluster_view" src="https://user-images.githubusercontent.com/71546117/201100267-3420fc5c-aa0d-4d04-8b91-2197fdc3e0d2.png">
> <img width="360" alt="desired" src="https://user-images.githubusercontent.com/71546117/201100285-b96b56bb-35be-439d-8f9a-05bb770108a9.png">
> 
> - When "show neighboring nodes semi-transparent" is disabled, previously semi-transparent nodes that were selected are now unselected (because they are not visible anymore)
> - It would also be desired adjust the scroll pane to center the selected nodes when changing view, graph, etc.

Tobias Holenstein has updated the pull request incrementally with one additional commit since the last revision:

  added missing validate

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11062/files
  - new: https://git.openjdk.org/jdk/pull/11062/files/f2521c3b..b74423b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11062&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11062&range=01-02

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11062.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11062/head:pull/11062

PR: https://git.openjdk.org/jdk/pull/11062