Once again remove Mania passive HP drain

osu.Game.Rulesets.Mania.Tests/ManiaHealthProcessorTest.cs

@@ -0,0 +1,31 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using NUnit.Framework;
+using osu.Game.Rulesets.Mania.Beatmaps;
+using osu.Game.Rulesets.Mania.Objects;
+using osu.Game.Rulesets.Mania.Scoring;
+
+namespace osu.Game.Rulesets.Mania.Tests
+{
+    [TestFixture]
+    public class ManiaHealthProcessorTest
+    {
+        [Test]
+        public void TestNoDrain()
+        {
+            var processor = new ManiaHealthProcessor(0);
+            processor.ApplyBeatmap(new ManiaBeatmap(new StageDefinition(4))
+            {
+                HitObjects =
+                {
+                    new Note { StartTime = 0 },
+                    new Note { StartTime = 1000 },
+                }
+            });
+
+            // No matter what, mania doesn't have passive HP drain.
+            Assert.That(processor.DrainRate, Is.Zero);
+        }
+    }
+}

osu.Game.Rulesets.Mania/Scoring/ManiaHealthProcessor.cs

@@ -15,6 +15,14 @@ namespace osu.Game.Rulesets.Mania.Scoring
         {
         }
 
+        protected override double ComputeDrainRate()
+        {
+            // Base call is run only to compute HP recovery.
+            base.ComputeDrainRate();
+
+            return 0;
+        }
+
         protected override IEnumerable<HitObject> EnumerateTopLevelHitObjects() => Beatmap.HitObjects;
 
         protected override IEnumerable<HitObject> EnumerateNestedHitObjects(HitObject hitObject) => hitObject.NestedHitObjects;