Add PathfinderGoalSit for diff visibility

src/main/java/net/minecraft/server/PathfinderGoalSit.java

@@ -0,0 +1,39 @@
+package net.minecraft.server;
+
+public class PathfinderGoalSit extends PathfinderGoal {
+
+    private EntityTameableAnimal a;
+    private boolean b = false;
+
+    public PathfinderGoalSit(EntityTameableAnimal entitytameableanimal) {
+        this.a = entitytameableanimal;
+        this.a(5);
+    }
+
+    public boolean a() {
+        if (!this.a.isTamed()) {
+            return false;
+        } else if (this.a.H()) {
+            return false;
+        } else if (!this.a.onGround) {
+            return false;
+        } else {
+            EntityLiving entityliving = this.a.getOwner();
+
+            return entityliving == null ? true : (this.a.e(entityliving) < 144.0D && entityliving.aC() != null ? false : this.b);
+        }
+    }
+
+    public void c() {
+        this.a.getNavigation().g();
+        this.a.setSitting(true);
+    }
+
+    public void d() {
+        this.a.setSitting(false);
+    }
+
+    public void a(boolean flag) {
+        this.b = flag;
+    }
+}