Relieve OsuScreen of back button input duties

osu.Game/Graphics/UserInterface/BackButton.cs

@@ -3,10 +3,12 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
+using osu.Framework.Input.Bindings;
+using osu.Game.Input.Bindings;
 
 namespace osu.Game.Graphics.UserInterface
 {
-    public class BackButton : TwoLayerButton
+    public class BackButton : TwoLayerButton, IKeyBindingHandler<GlobalAction>
     {
         public BackButton()
         {
@@ -22,5 +24,18 @@ namespace osu.Game.Graphics.UserInterface
             BackgroundColour = colours.Pink;
             HoverColour = colours.PinkDark;
         }
+
+        public bool OnPressed(GlobalAction action)
+        {
+            if (action == GlobalAction.Back)
+            {
+                Action?.Invoke();
+                return true;
+            }
+
+            return false;
+        }
+
+        public bool OnReleased(GlobalAction action) => action == GlobalAction.Back;
     }
 }

osu.Game/OsuGame.cs

@@ -406,6 +406,11 @@ namespace osu.Game
                             Anchor = Anchor.BottomLeft,
                             Origin = Anchor.BottomLeft,
                             Alpha = 0,
+                            Action = () =>
+                            {
+                                if ((screenStack.CurrentScreen as IOsuScreen)?.AllowBackButton == true)
+                                    screenStack.Exit();
+                            }
                         },
                         logoContainer = new Container { RelativeSizeAxes = Axes.Both },
                     }

osu.Game/Screens/OsuScreen.cs

@@ -8,10 +8,8 @@ using osu.Framework.Audio;
 using osu.Framework.Audio.Sample;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
-using osu.Framework.Input.Bindings;
 using osu.Framework.Screens;
 using osu.Game.Beatmaps;
-using osu.Game.Input.Bindings;
 using osu.Game.Rulesets;
 using osu.Game.Screens.Menu;
 using osu.Game.Overlays;
@@ -21,7 +19,7 @@ using osu.Game.Rulesets.Mods;
 
 namespace osu.Game.Screens
 {
-    public abstract class OsuScreen : Screen, IOsuScreen, IKeyBindingHandler<GlobalAction>, IHasDescription
+    public abstract class OsuScreen : Screen, IOsuScreen, IHasDescription
     {
         /// <summary>
         /// The amount of negative padding that should be applied to game background content which touches both the left and right sides of the screen.
@@ -133,21 +131,6 @@ namespace osu.Game.Screens
             sampleExit = audio.Samples.Get(@"UI/screen-back");
         }
 
-        public virtual bool OnPressed(GlobalAction action)
-        {
-            if (!this.IsCurrentScreen()) return false;
-
-            if (action == GlobalAction.Back && AllowBackButton)
-            {
-                this.Exit();
-                return true;
-            }
-
-            return false;
-        }
-
-        public bool OnReleased(GlobalAction action) => action == GlobalAction.Back && AllowBackButton;
-
         public override void OnResuming(IScreen last)
         {
             if (PlayResumeSound)

osu.Game/Screens/Select/SongSelect.cs

@@ -34,10 +34,11 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input.Bindings;
 
 namespace osu.Game.Screens.Select
 {
-    public abstract class SongSelect : OsuScreen
+    public abstract class SongSelect : OsuScreen, IKeyBindingHandler<GlobalAction>
     {
         private static readonly Vector2 wedged_container_size = new Vector2(0.5f, 245);
 
@@ -645,7 +646,7 @@ namespace osu.Game.Screens.Select
                 Schedule(() => BeatmapDetails.Leaderboard.RefreshScores())));
         }
 
-        public override bool OnPressed(GlobalAction action)
+        public virtual bool OnPressed(GlobalAction action)
         {
             if (!this.IsCurrentScreen()) return false;
 
@@ -656,9 +657,11 @@ namespace osu.Game.Screens.Select
                     return true;
             }
 
-            return base.OnPressed(action);
+            return false;
         }
 
+        public bool OnReleased(GlobalAction action) => action == GlobalAction.Select;
+
         protected override bool OnKeyDown(KeyDownEvent e)
         {
             if (e.Repeat) return false;