feat(GTK Window): Extend into Title Bar

[lindexi]

GitHub Issue (If applicable): #10874, closes #10368

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

We can not extned into title bar in GTK

What is the new behavior?

We can use the Decorated window in GTK by set CoreApplication.GetCurrentView().TitleBar.ExtendViewIntoTitleBar = true

Copilot Summary

🤖 Generated by Copilot at e1f5054

This pull request adds support for the ExtendViewIntoTitleBar feature on the Skia.Gtk platform. It enables the CoreApplicationViewTitleBar class and its property for Skia apps, and updates the window decoration accordingly.

PR Checklist

Please check if your PR fulfills the following requirements:

• Docs have been added/updated which fit documentation template (for bug fixes / features)
• Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
• Validated PR Screenshots Compare Test Run results.
• Contains NO breaking changes
• Associated with an issue (GitHub or internal) and uses the automatic close keywords.
• Commits must be following the Conventional Commits specification.

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How can I add the UITest to test the application startup?

Can I know current application are running with GTK?

[ajpinedam]

Change looks good. Thanks for the update.

[MartinZikmund]

👍👍👍

[lindexi]

Thank you @MartinZikmund and @ajpinedam

[lindexi]

Usage:

        var host = new GtkHost(() =>
        {
            var app = new AppHead();
            CoreApplication.GetCurrentView().TitleBar.ExtendViewIntoTitleBar = true;
            return app;
        });