Reduce the number of delayed tasks on chromium run loop

components/scheduler/base/task_queue_manager_unittest.cc

 // Copyright 2014 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 "components/scheduler/base/task_queue_manager.h"
 
 #include "base/location.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/test/simple_test_tick_clock.h"
@@ skipping 1440 matching lines @@
 
   domain_b->AdvanceTo(start_time + base::TimeDelta::FromMilliseconds(50));
 
   test_task_runner_->RunUntilIdle();
   EXPECT_THAT(run_order, ElementsAre(1, 2, 3, 4));
 
   manager_->UnregisterTimeDomain(domain_a);
   manager_->UnregisterTimeDomain(domain_b);
 }
 
+namespace {
+void ChromiumRunloopInspectionTask(
+    scoped_refptr<cc::OrderedSimpleTaskRunner> test_task_runner) {
+  EXPECT_EQ(1u, test_task_runner->NumPendingTasks());
+}
+}  // namespace
+
+TEST_F(TaskQueueManagerTest, NumberOfPendingTasksOnChromiumRunLoop) {
+  Initialize(1u);
+
+  // NOTE because tasks posted to the chromiumrun loop are not cancellable, we
+  // will end up with a lot more tasks posted if the delayed tasks were posted
+  // in the reverse order.
+  // TODO(alexclarke): Consider talking to the message pump directly.
+  test_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
+  for (int i = 1; i < 100; i++) {
+    runners_[0]->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&ChromiumRunloopInspectionTask, test_task_runner_),
+        base::TimeDelta::FromMilliseconds(i));
+  }
+  test_task_runner_->RunUntilIdle();
+}
+
 }  // namespace scheduler