Add trayicon menu export support for osx.

native/Avalonia.Native/src/OSX/trayicon.mm

@@ -1,5 +1,6 @@
 #include "common.h"
 #include "trayicon.h"
+#include "menu.h"
 
 extern IAvnTrayIcon* CreateTrayIcon(IAvnTrayIconEvents* cb)
 {
@@ -52,7 +53,12 @@ HRESULT AvnTrayIcon::SetMenu (IAvnMenu* menu)
     
     @autoreleasepool
     {
+        auto appMenu = dynamic_cast<AvnAppMenu*>(menu);
         
+        if(appMenu != nullptr)
+        {
+            [_native setMenu:appMenu->GetNative()];
+        }
     }
     
     return  S_OK;

src/Avalonia.Native/AvaloniaNativeMenuExporter.cs

@@ -17,6 +17,7 @@ namespace Avalonia.Native
         private IAvnWindow _nativeWindow;
         private NativeMenu _menu;
         private __MicroComIAvnMenuProxy _nativeMenu;
+        private IAvnTrayIcon _trayIcon;
 
         public AvaloniaNativeMenuExporter(IAvnWindow nativeWindow, IAvaloniaNativeFactory factory)
         {
@@ -33,6 +34,14 @@ namespace Avalonia.Native
             DoLayoutReset();
         }
 
+        public AvaloniaNativeMenuExporter(IAvnTrayIcon trayIcon, IAvaloniaNativeFactory factory)
+        {
+            _factory = factory;
+            _trayIcon = trayIcon;
+            
+            DoLayoutReset();
+        }
+
         public bool IsNativeMenuExported => _exported;
 
         public event EventHandler OnIsNativeMenuExportedChanged;
@@ -82,15 +91,25 @@ namespace Avalonia.Native
 
                 if (_nativeWindow is null)
                 {
-                    var appMenu = NativeMenu.GetMenu(Application.Current);
+                    if (_trayIcon is null)
+                    {
+                        var appMenu = NativeMenu.GetMenu(Application.Current);
+
+                        if (appMenu == null)
+                        {
+                            appMenu = CreateDefaultAppMenu();
+                            NativeMenu.SetMenu(Application.Current, appMenu);
+                        }
 
-                    if (appMenu == null)
+                        SetMenu(appMenu);
+                    }
+                    else
                     {
-                        appMenu = CreateDefaultAppMenu();
-                        NativeMenu.SetMenu(Application.Current, appMenu);
+                        if (_menu != null)
+                        {
+                            SetMenu(_trayIcon, _menu);
+                        }
                     }
-
-                    SetMenu(appMenu);
                 }
                 else
                 {
@@ -171,5 +190,26 @@ namespace Avalonia.Native
                 avnWindow.SetMainMenu(_nativeMenu);
             }
         }
+
+        private void SetMenu(IAvnTrayIcon trayIcon, NativeMenu menu)
+        {
+            var setMenu = false;
+
+            if (_nativeMenu is null)
+            {
+                _nativeMenu = __MicroComIAvnMenuProxy.Create(_factory);
+
+                _nativeMenu.Initialize(this, menu, "");     
+
+                setMenu = true;           
+            }
+
+            _nativeMenu.Update(_factory, menu);
+
+            if(setMenu)
+            {
+                trayIcon.SetMenu(_nativeMenu);
+            }
+        }
     }
 }

src/Avalonia.Native/TrayIconImpl.cs

@@ -31,6 +31,8 @@ namespace Avalonia.Native
         public TrayIconImpl(IAvaloniaNativeFactory factory)
         {
             _native = factory.CreateTrayIcon(new TrayIconEvents(this));
+
+            MenuExporter = new AvaloniaNativeMenuExporter(_native, factory);
         }
         
         public void Dispose()