Disabling NumTasksBeforeDetach in base_unittests due to flakiness

base/task_scheduler/scheduler_worker_pool_impl_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/task_scheduler/scheduler_worker_pool_impl.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <unordered_set>
@@ skipping 701 matching lines @@
   //   beginning of the test.
   EXPECT_EQ(static_cast<int>(kNumWorkersInWorkerPool),
             histogram->SnapshotSamples()->GetCount(1));
   EXPECT_EQ(0, histogram->SnapshotSamples()->GetCount(10));
 
   tasks_can_exit_event.Signal();
   worker_pool_->WaitForAllWorkersIdleForTesting();
   worker_pool_->DisallowWorkerDetachmentForTesting();
 }
 
-TEST_F(TaskSchedulerWorkerPoolHistogramTest, NumTasksBeforeDetach) {
+// TODO(crbug.com/698046): disabled due to flakyness.
+TEST_F(TaskSchedulerWorkerPoolHistogramTest, DISABLED_NumTasksBeforeDetach) {
   InitializeWorkerPool(kReclaimTimeForDetachTests, kNumWorkersInWorkerPool);
 
   auto histogrammed_thread_task_runner =
       worker_pool_->CreateSequencedTaskRunnerWithTraits(
           TaskTraits().WithBaseSyncPrimitives());
 
   // Post 3 tasks and hold the thread for idle thread stack ordering.
   // This test assumes |histogrammed_thread_task_runner| gets assigned the same
   // thread for each of its tasks.
   PlatformThreadRef thread_ref;
@@ skipping 117 matching lines @@
                                 StandbyThreadPolicy::ONE, 8U, TimeDelta::Max()),
       Bind(&NotReachedReEnqueueSequenceCallback), &task_tracker,
       &delayed_task_manager);
   ASSERT_TRUE(worker_pool);
   EXPECT_EQ(1U, worker_pool->NumberOfAliveWorkersForTesting());
   worker_pool->JoinForTesting();
 }
 
 }  // namespace internal
 }  // namespace base