Add specific samples for dialog 'Ok' and 'Cancel' buttons

osu.Game/Graphics/UserInterface/HoverSampleSet.cs

@@ -20,6 +20,12 @@ public enum HoverSampleSet
         TabSelect,
 
         [Description("scrolltotop")]
-        ScrollToTop
+        ScrollToTop,
+
+        [Description("dialog-cancel")]
+        DialogCancel,
+
+        [Description("dialog-ok")]
+        DialogOk
     }
 }

osu.Game/Overlays/Dialog/PopupDialogButton.cs

@@ -8,7 +8,8 @@ namespace osu.Game.Overlays.Dialog
 {
     public class PopupDialogButton : DialogButton
     {
-        public PopupDialogButton()
+        public PopupDialogButton(HoverSampleSet sampleSet = HoverSampleSet.Button)
+            : base(sampleSet)
         {
             Height = 50;
             BackgroundColour = Color4Extensions.FromHex(@"150e14");

osu.Game/Overlays/Dialog/PopupDialogCancelButton.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Allocation;
 using osu.Game.Graphics;
+using osu.Game.Graphics.UserInterface;
 
 namespace osu.Game.Overlays.Dialog
 {
@@ -13,5 +14,10 @@ private void load(OsuColour colours)
         {
             ButtonColour = colours.Blue;
         }
+
+        public PopupDialogCancelButton()
+            : base(HoverSampleSet.DialogCancel)
+        {
+        }
     }
 }

osu.Game/Overlays/Dialog/PopupDialogOkButton.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Allocation;
 using osu.Game.Graphics;
+using osu.Game.Graphics.UserInterface;
 
 namespace osu.Game.Overlays.Dialog
 {
@@ -13,5 +14,10 @@ private void load(OsuColour colours)
         {
             ButtonColour = colours.Pink;
         }
+
+        public PopupDialogOkButton()
+            : base(HoverSampleSet.DialogOk)
+        {
+        }
     }
 }