Allows MenuBar to be created in a background thread by delaying MenuBarSkin::rebuildUI() call until after the MenuBar becomes a part of the scene graph.
------------- Commit messages: - spelling - use system menu - cleanup - possible fix - test Changes: https://git.openjdk.org/jfx/pull/1727/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1727&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8350976 Stats: 67 lines in 2 files changed: 56 ins; 7 del; 4 mod Patch: https://git.openjdk.org/jfx/pull/1727.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/1727/head:pull/1727 PR: https://git.openjdk.org/jfx/pull/1727
