RFR: 8252811: The list of cells in a VirtualFlow is cleared every time the number of items changes

[Jeanette Winzenburg]

On Fri, 18 Sep 2020 11:07:36 GMT, Ajit Ghaisas <aghaisas at openjdk.org> wrote:

>> This PR removes an old fix (RT-13965/JDK-8113318), which was applied in 2011 to avoid a memory leak in
>> `VirtualFlow::sheetChildren`, after new items were constantly added.
>> With the current VirtualFlow implementation, there are in place the necessary methods that take care of cleaning or
>> adding new cells to the sheetChildren list, and such memory leak doesn't exist, the size remains constant when new
>> items are added or removed (see included unity test).   The call to `sheetchildren.clear()`, on the contrary, has a big
>> impact in performance and CPU usage, when new items are constantly added, as has been reported in JDK-8185886/#108.
>
> Marked as reviewed by aghaisas (Reviewer).

Just a note: fixing this makes [JDK-8244826](https://bugs.openjdk.java.net/browse/JDK-8244826) disappear - not entirely
certain, if it's really a fix for that one or only smearing over it.

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

PR: https://git.openjdk.java.net/jfx/pull/298