Drop AppTheme flag (#11368)

Xamarin.Forms.ControlGallery.Android/FormsAppCompatActivity.cs

@@ -45,7 +45,7 @@ namespace Xamarin.Forms.ControlGallery.Android
 
 #if TEST_EXPERIMENTAL_RENDERERS
 #else
-			Forms.SetFlags("UseLegacyRenderers", "SwipeView_Experimental", "MediaElement_Experimental", "AppTheme_Experimental");
+			Forms.SetFlags("UseLegacyRenderers", "SwipeView_Experimental", "MediaElement_Experimental");
 #endif
 			Forms.Init(this, bundle);
 

Xamarin.Forms.ControlGallery.WindowsUniversal/App.xaml.cs

@@ -71,7 +71,7 @@ namespace Xamarin.Forms.ControlGallery.WindowsUniversal
 
                 rootFrame.NavigationFailed += OnNavigationFailed;
 
-				Forms.SetFlags("Shell_UWP_Experimental", "SwipeView_Experimental", "MediaElement_Experimental", "AppTheme_Experimental");
+				Forms.SetFlags("Shell_UWP_Experimental", "SwipeView_Experimental", "MediaElement_Experimental");
 				Forms.Init (e);
 				//FormsMaps.Init (Controls.App.Config["UWPMapsAuthKey"]);
 

Xamarin.Forms.ControlGallery.iOS/AppDelegate.cs

@@ -151,7 +151,7 @@ namespace Xamarin.Forms.ControlGallery.iOS
 			App.IOSVersion = int.Parse(versionPart[0]);
 
 			Xamarin.Calabash.Start();
-			Forms.SetFlags("SwipeView_Experimental", "MediaElement_Experimental", "AppTheme_Experimental");
+			Forms.SetFlags("SwipeView_Experimental", "MediaElement_Experimental");
 			Forms.Init();
 			FormsMaps.Init();
 #if __XCODE11__

Xamarin.Forms.Controls/GalleryPages/AppThemeGalleries/AppThemeGallery.cs

@@ -42,8 +42,6 @@
 			button.Text = "AppTheme Enabled!";
 			button.TextColor = Color.Black;
 			button.IsEnabled = false;
-
-			Device.SetFlags(new[] { ExperimentalFlags.AppThemeExperimental });
 		}
 	}
 }

Xamarin.Forms.Core.UnitTests/AppThemeTests.cs

@@ -10,8 +10,6 @@ namespace Xamarin.Forms.Core.UnitTests
 		{
 			base.Setup();
 			Application.Current = new MockApplication();
-
-			Device.SetFlags(new[] { ExperimentalFlags.AppThemeExperimental });
 		}
 
 		[Test]

Xamarin.Forms.Core/Application.cs

@@ -189,9 +189,6 @@ namespace Xamarin.Forms
 
 		void TriggerThemeChangedActual(AppThemeChangedEventArgs args)
 		{
-			if (Device.Flags == null || Device.Flags.IndexOf(ExperimentalFlags.AppThemeExperimental) == -1)
-				return;
-
 			// On iOS the event is triggered more than once.
 			// To minimize that for us, we only do it when the theme actually changes and it's not currently firing
 			if (_themeChangedFiring || RequestedTheme == _lastAppTheme)

Xamarin.Forms.Core/BindableObjectExtensions.cs

@@ -68,11 +68,7 @@ namespace Xamarin.Forms
 			return returnIfNotSet;
 		}
 
-		public static void SetOnAppTheme<T>(this BindableObject self, BindableProperty targetProperty, T light, T dark)
-		{
-			ExperimentalFlags.VerifyFlagEnabled(nameof(BindableObjectExtensions), ExperimentalFlags.AppThemeExperimental, nameof(BindableObjectExtensions), nameof(SetOnAppTheme));
-			self.SetBinding(targetProperty, new AppThemeBinding { Light = light, Dark = dark});
-		}
+		public static void SetOnAppTheme<T>(this BindableObject self, BindableProperty targetProperty, T light, T dark) => self.SetBinding(targetProperty, new AppThemeBinding { Light = light, Dark = dark});
 
 		public static void SetAppThemeColor(this BindableObject self, BindableProperty targetProperty, Color light, Color dark) => SetOnAppTheme(self, targetProperty, light, dark);
 	}

Xamarin.Forms.Core/ExperimentalFlags.cs

@@ -7,14 +7,13 @@ using System.Text;
 
 namespace Xamarin.Forms
 {
-	internal static class ExperimentalFlags
+	static class ExperimentalFlags
 	{
 		internal const string ShellUWPExperimental = "Shell_UWP_Experimental";
 		internal const string CarouselViewExperimental = "CarouselView_Experimental";
 		internal const string SwipeViewExperimental = "SwipeView_Experimental";
 		internal const string MediaElementExperimental = "MediaElement_Experimental";
 		internal const string MarkupExperimental = "Markup_Experimental";
-		internal const string AppThemeExperimental = "AppTheme_Experimental";
 		internal const string ExpanderExperimental = "Expander_Experimental";
 		internal const string RadioButtonExperimental = "RadioButton_Experimental";
 		internal const string ShapesExperimental = "Shapes_Experimental";

Xamarin.Forms.Xaml.UnitTests/OnAppThemeTests.cs

@@ -11,7 +11,6 @@ namespace Xamarin.Forms.Xaml.UnitTests
 		public override void Setup()
 		{
 			base.Setup();
-			Device.SetFlags(new[] { "AppTheme_Experimental" });
 			Application.Current = new MockApplication();
 		}
 

Xamarin.Forms.Xaml/MarkupExtensions/AppThemeBindingExtension.cs

@@ -14,11 +14,6 @@ namespace Xamarin.Forms.Xaml
 		object _dark;
 		bool _hasdark;
 
-		public AppThemeBindingExtension()
-		{
-			ExperimentalFlags.VerifyFlagEnabled(nameof(AppThemeBindingExtension), ExperimentalFlags.AppThemeExperimental, nameof(AppThemeBindingExtension));
-		}
-
 		public object Default
 		{
 			get => _default; set