Fix warning message on Mac about secure coding not enabled

[Phillipus]

• See [Mac Sonoma] "WARNING: Secure coding is not enabled for restorable state" warning message #1228

• On macOS 14 and later a warning message is written to console:

"WARNING: Secure coding is not enabled for restorable state! Enable secure coding by implementing NSApplicationDelegate.applicationSupportsSecureRestorableState: and returning YES."

• As recommended by Apple, this change adds a new selector for applicationSupportsSecureRestorableState and returns a 1 value (YES) in the callback in the Display class

• However, this only takes care of the NSApplicationDelegate created in the Display class. The warning message will still appear when a splash screen is created in Equinox JNI code so a fix there is also required. See [Mac Sonoma] "WARNING: Secure coding is not enabled for restorable state" warning message eclipse-equinox/equinox#630

• This implementation for SWT can be tested by using the -noSplash argument when launching Eclipse

[github-actions]

Test Results

   418 files  ±0     418 suites  ±0   7m 19s ⏱️ -8s
 4 121 tests ±0   4 113 ✅ ±0   8 💤 ±0  0 ❌ ±0 
16 313 runs  ±0  16 221 ✅ ±0  92 💤 ±0  0 ❌ ±0 

Results for commit 986b71c. ± Comparison against base commit d3df796.

[lshanmug]

@Phillipus Changes look good. Should we merge for 4.32 RC1?

[Phillipus]

@Phillipus Changes look good. Should we merge for 4.32 RC1?

@lshanmug The applicationSupportsSecureRestorableState selector was added in macOS 12 (see here) so I guess the selector is simply ignored on earlier macOS? So I think it's safe to merge.

But as mentioned above, equinox project also need to apply a fix in their native Mac code. I create a PR for that case here.

[lshanmug]

@Phillipus Changes look good. Should we merge for 4.32 RC1?

@lshanmug The applicationSupportsSecureRestorableState selector was added in macOS 12 (see here) so I guess the selector is simply ignored on earlier macOS? So I think it's safe to merge.

Yes, the selector code will not be called for earlier versions.

But as mentioned above, equinox project also need to apply a fix in their native Mac code. I create a PR for that case here.

The SWT PR can go in anyways, correct?

[Phillipus]

The SWT PR can go in anyways correct?

Yes, I think so. If Eclipse is started with the -noSplash option then the SWT selector is invoked and there is no warning message, as desired.

One thing I don't understand is where is the singleton NSApplication created? Equinox references [NSApplication sharedApplication] here and SWT references it in the Display class.

[lshanmug]

One thing I don't understand is where is the singleton NSApplication created? Equinox references [NSApplication sharedApplication] here and SWT references it in the Display class.

NSApplication.sharedApplication itself creates the NSApplication instance for the first time and returns it for future calls. Please see doc.