RFR: JDK-8255439: System Tray icons get corrupted when windows scaling changes [v6]

[Harshitha Onkar]

> 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 incrementally with one additional commit since the last revision:

  new changes - trayicon update triggered in WmTaskbarCreated

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8441/files
  - new: https://git.openjdk.java.net/jdk/pull/8441/files/532868e7..eff226f9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8441&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8441&range=04-05

  Stats: 71 lines in 5 files changed: 30 ins; 29 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8441.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8441/head:pull/8441

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