RFR: 8269115: WebView paste event contains old data [v6]

[Jay Bhaskar]

> Issue: The DataObject uses m_availMimeTypes as Vector of strings, and appending mime types in pasteboard operation like setPlainText, Hence it will append duplicate mime types in m_availMimeTypes , in this case the length clipboardData.types would be wrong, and duplicates data would be copied to clipboard target.
> Solution: Use ListHashSet data Structure instead of Vector for m_availMimeTypes.

Jay Bhaskar has updated the pull request incrementally with five additional commits since the last revision:

 - added manual test
 - Add new Test case for copy and paste clipboard
 - Add new Test case for copy and paste clipboard
 - new test case
 - new test case

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Changes:
  - all: https://git.openjdk.java.net/jfx/pull/729/files
  - new: https://git.openjdk.java.net/jfx/pull/729/files/aa75ea4e..2b1c9eef

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=729&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=729&range=04-05

  Stats: 230 lines in 3 files changed: 204 ins; 16 del; 10 mod
  Patch: https://git.openjdk.java.net/jfx/pull/729.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/729/head:pull/729

PR: https://git.openjdk.java.net/jfx/pull/729