Add pulling taking up a hand (#2405)

* Add pulling taking up a hand

* Revert unnecessary refactor

Content.Shared/Physics/Pull/PullAttemptMessage.cs

@@ -0,0 +1,11 @@
+using Robust.Shared.GameObjects.Components;
+
+namespace Content.Shared.Physics.Pull
+{
+    public class PullAttemptMessage : PullMessage
+    {
+        public PullAttemptMessage(IPhysicsComponent puller, IPhysicsComponent pulled) : base(puller, pulled) { }
+
+        public bool Cancelled { get; set; }
+    }
+}

Content.Shared/Physics/Pull/PullController.cs

@@ -100,6 +100,22 @@ namespace Content.Shared.Physics.Pull
                 return false;
             }
 
+            var pullAttempt = new PullAttemptMessage(puller, ControlledComponent);
+
+            puller.Owner.SendMessage(null, pullAttempt);
+
+            if (pullAttempt.Cancelled)
+            {
+                return false;
+            }
+
+            ControlledComponent.Owner.SendMessage(null, pullAttempt);
+
+            if (pullAttempt.Cancelled)
+            {
+                return false;
+            }
+
             _puller = puller;
 
             var message = new PullStartedMessage(this, _puller, ControlledComponent);