scheduler: Remove task observer shenanigans

components/scheduler/child/idle_helper_unittest.cc

Index: components/scheduler/child/idle_helper_unittest.cc
diff --git a/components/scheduler/child/idle_helper_unittest.cc b/components/scheduler/child/idle_helper_unittest.cc
index 3ee49c49f0226ac2201d6bc7fef8f2e706127130..c21faf06251ee4781965b8725b16d7f562ef988b 100644
--- a/components/scheduler/child/idle_helper_unittest.cc
+++ b/components/scheduler/child/idle_helper_unittest.cc
@@ -826,7 +826,7 @@ TEST_F(IdleHelperTest, TestLongIdlePeriodRestartWaitsIfNotMaxDeadline) {
 
   // Once the pending task is run the new idle period should start.
   clock_->Advance(pending_task_delay - idle_task_duration);
-  RunUntilIdle();
+
   // Since the idle period tried to start before the pending task ran we have to
   // wait for the idle helper to retry starting the long idle period.
   clock_->Advance(retry_enable_long_idle_period_delay());