RFR: JDK-8297449: Update JInternalFrame Metal Border code [v3]

[Alexey Ivanov]

On Tue, 29 Nov 2022 20:05:49 GMT, Harshitha Onkar <honkar at openjdk.org> wrote:

>> Updated Metal Border code for JInternalFrame. 
>> 
>> - Added instanceof check before casting Graphics to G2D.
>> - Replaced roundHalfDown with Region.clipRound()
>
> Harshitha Onkar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   added scaleFactor

src/java.desktop/share/classes/javax/swing/plaf/metal/MetalBorders.java line 277:

> 275:                 at = g2d.getTransform();
> 276:                 scaleFactor = at.getScaleX();
> 277:                 oldColor = g2d.getColor();

Color wasn't preserved before [JDK-8015739](https://bugs.openjdk.org/browse/JDK-8015739).

Getting and setting the color doesn't require `Graphics2D`, so, if it's to be preserved, it should be preserved outside of `instanceof`.

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PR: https://git.openjdk.org/jdk/pull/11305