Clean up hack avoiding infinite loop in unit test.

ui/aura/gestures/gesture_recognizer_unittest.cc

Index: ui/aura/gestures/gesture_recognizer_unittest.cc
diff --git a/ui/aura/gestures/gesture_recognizer_unittest.cc b/ui/aura/gestures/gesture_recognizer_unittest.cc
index 1392d6064bfbe659cd26d767cf55d7de91c55bd0..e102c2288f560668b70012a7284631187611a4c5 100644
--- a/ui/aura/gestures/gesture_recognizer_unittest.cc
+++ b/ui/aura/gestures/gesture_recognizer_unittest.cc
@@ -600,9 +600,6 @@ class RemoveOnTouchCancelHandler : public TestEventHandler {
     TestEventHandler::OnTouchEvent(event);
     if (event->type() == ui::ET_TOUCH_CANCELLED) {
       Window* target = static_cast<Window*>(event->target());
-      // This is tiptoeing around crbug.com/310172. If this event handler isn't
-      // removed, we enter an infinite loop.
-      target->RemovePreTargetHandler(this);
       target->parent()->RemoveChild(target);
     }
   }