Add icon next to beatmap title/username to open in browser

osu.Game/Graphics/UserInterface/ExternalLinkButton.cs

@@ -0,0 +1,58 @@
+using System.Diagnostics;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Cursor;
+using osu.Framework.Input;
+using OpenTK.Graphics;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public class ExternalLinkButton : CompositeDrawable, IHasTooltip
+    {
+        public string Link { get; set; }
+
+        private Color4 hoverColour;
+
+        public ExternalLinkButton(string link = null)
+        {
+            Link = link;
+            InternalChild = new SpriteIcon
+            {
+                Icon = FontAwesome.fa_external_link,
+                RelativeSizeAxes = Axes.Both
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            hoverColour = colours.Yellow;
+        }
+
+        protected override bool OnHover(InputState state)
+        {
+            InternalChild.FadeColour(hoverColour, 500, Easing.OutQuint);
+            return base.OnHover(state);
+        }
+
+        protected override void OnHoverLost(InputState state)
+        {
+            InternalChild.FadeColour(Color4.White, 500, Easing.OutQuint);
+            base.OnHoverLost(state);
+        }
+
+        protected override bool OnClick(InputState state)
+        {
+            if(Link != null)
+                Process.Start(new ProcessStartInfo
+                {
+                    FileName = Link,
+                    UseShellExecute = true //see https://github.com/dotnet/corefx/issues/10361
+                });
+            return true;
+        }
+
+        public string TooltipText => "View in browser";
+    }
+}