RFR: 8247576: Labeled/SkinBase: misbehavior on switching skin [v2]

[Jeanette Winzenburg]

> Cleanup of LabeledSkinBase to allow for switching skins
> 
> - removed null check in listener on graphic's layoutBounds
> - added removal of listener in dispose

Jeanette Winzenburg has updated the pull request incrementally with one additional commit since the last revision:

  removed outdated code comment

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

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/355/files
  - new: https://git.openjdk.java.net/jfx/pull/355/files/10c9f485..31b3ac08

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=355&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=355&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/355.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/355/head:pull/355

PR: https://git.openjdk.java.net/jfx/pull/355