RFR: JDK-8255439: System Tray icons get corrupted when windows scaling changes [v8]

[Harshitha Onkar]

On Fri, 13 May 2022 18:01:47 GMT, Harshitha Onkar <duke at openjdk.java.net> wrote:

>> In Windows, when desktop scaling is changed the tray icons was distorted/blurred a bit each time scaling changes.
>> 
>> With the proposed fix, the tray icon scales according to on-the-fly DPI scale settings. A test case has been added which adds a MRI icon to system tray, to observe the icon scaling when DPI is changed. Since the scale cannot be programmatically changed (for dynamic on-the-fly scale changes), I have used a manual test case to test this scenario.
>> 
>> When DPI changes usually two messages are sent by windows -
>> 
>> - [WM_DPICHANGED](https://docs.microsoft.com/en-us/windows/win32/hidpi/wm-dpichanged)
>> - [WMPOSCHANGING](https://docs.microsoft.com/en-us/windows/win32/winmsg/wm-windowposchanging)
>> 
>> I'm triggering an update on tray icons on receiving WMPOSCHANGING msg through the Tray icon's Window Procedure. Triggering an update on WM_DPICHANGED was still causing the icons to be distorted, hence WMPOSCHANGING is being used as the message to trigger the update.
>
> Harshitha Onkar has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 11 additional commits since the last revision:
> 
>  - Merge branch 'master' into WinTrayIcon
>  - reverted SystemTray changes
>  - new changes - trayicon update triggered in WmTaskbarCreated
>  - trayicon update triggered on taskbar reload
>  - test case exit issue fix
>  - formatting changes
>  - resized instruction window and formatted line lengths
>  - removed whitespaces error due to CRLF
>  - removed whitespace error
>  - added manual to test case
>  - ... and 1 more: https://git.openjdk.java.net/jdk/compare/0f7d36fd...60391f28

Changes incorporated:

- Added env->ExceptionClear() 
- Fixed CI debug build issue due to variable mismatch
- Added changes suggested by @prrace , @kevinrushforth and @aivanov-jdk

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PR: https://git.openjdk.java.net/jdk/pull/8441