RFR: 8284294: Create an automated regression test for RFE 4138746 [v2]

[Manukumar V S]

> Create an automated regression test for [JDK-4138746](https://bugs.openjdk.java.net/browse/JDK-4138746)
> 
> Issue:
> In the following example (and similarly with other components) you cannot specify the correct character to underline:
> 
> JLabel label = new JLabel ("Save As...");
> label.setDisplayedMnemonic ('A');
> 
> The 'A' in 'As' should be underlined (that's the intention at least), but the 'a' in 'Save' is what gets underlined.
> 
> The problem (aside from the lack of an API to specify exactly what should be underlined) is in the javax.swing.plaf.basic.BasicGraphicUtils drawString method which underlines the first character (upper OR lowercase) that matches the mnemonic character.
> 
> Fix:
> A new property "displayedMnemonicIndex" is introduced
> in classes AbstractButton and JLabel. It tells which
> character to underline. So for example to underline
> the capital 'A' in 'Save As', one should call:
>     setMnemonic('A');
>     setDisplayedMnemonicIndex(5);
> 
> Testing:
> Tested in Mach5 10 times per platform and got all Pass.

Manukumar V S has updated the pull request incrementally with one additional commit since the last revision:

  Fixed one wrong conditional check: removed ! operator from 'if (focusGainedLatch.await(3, TimeUnit.SECONDS))'

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8093/files
  - new: https://git.openjdk.java.net/jdk/pull/8093/files/9c951603..40bbfaac

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8093&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8093&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8093.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8093/head:pull/8093

PR: https://git.openjdk.java.net/jdk/pull/8093