RFR: 8293444: Creating ScrollPane with same content component causes memory leak [v3]

[Andy Goryachev]

> Using Weak*Listeners eliminates the memory leak.

Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:

  8293444: review comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/900/files
  - new: https://git.openjdk.org/jfx/pull/900/files/02330d09..0b22c2c9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=900&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=900&range=01-02

  Stats: 31 lines in 1 file changed: 20 ins; 8 del; 3 mod
  Patch: https://git.openjdk.org/jfx/pull/900.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/900/head:pull/900

PR: https://git.openjdk.org/jfx/pull/900