Reduce the number of delayed tasks on chromium run loop

components/scheduler/base/time_domain_unittest.cc

 // Copyright 2015 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/time_domain.h"
 
 #include "base/test/simple_test_tick_clock.h"
 #include "cc/test/ordered_simple_task_runner.h"
 #include "components/scheduler/base/task_queue_impl.h"
 #include "components/scheduler/base/task_queue_manager.h"
 #include "components/scheduler/base/task_queue_manager_delegate_for_test.h"
 #include "components/scheduler/base/test_time_source.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 using testing::_;
+using testing::Mock;
 
 namespace scheduler {
 
 class MockTimeDomain : public TimeDomain {
  public:
   MockTimeDomain()
       : now_(base::TimeTicks() + base::TimeDelta::FromSeconds(1)) {}
 
   using TimeDomain::NextScheduledRunTime;
   using TimeDomain::NextScheduledTaskQueue;
   using TimeDomain::ScheduleDelayedWork;
   using TimeDomain::UnregisterQueue;
   using TimeDomain::UpdateWorkQueues;
 
   // TimeSource implementation:
   LazyNow CreateLazyNow() override { return LazyNow(now_); }
 
   void AsValueIntoInternal(
       base::trace_event::TracedValue* state) const override {}
 
   bool MaybeAdvanceTime() override { return false; }
+  const char* GetName() const override { return "Test"; }
+  void OnRegisterWithTaskQueueManager(
+      TaskQueueManagerDelegate* task_queue_manager_delegate,
+      base::Closure do_work_closure) override {}
 
-  const char* GetName() const override { return "Test"; }
-
-  MOCK_METHOD1(RequestWakeup, void(base::TimeDelta delay));
+  MOCK_METHOD2(RequestWakeup, void(LazyNow* lazy_now, base::TimeDelta delay));
 
   void SetNow(base::TimeTicks now) { now_ = now; }
 
   base::TimeTicks Now() const { return now_; }
 
  private:
   base::TimeTicks now_;
 
   ~MockTimeDomain() override {}
 
   DISALLOW_COPY_AND_ASSIGN(MockTimeDomain);
 };
 
 class TimeDomainTest : public testing::Test {
  public:
   void SetUp() final {
     time_domain_ = make_scoped_refptr(new MockTimeDomain());
     task_queue_ = make_scoped_refptr(new internal::TaskQueueImpl(
         nullptr, time_domain_, TaskQueue::Spec("test_queue"), "test.category",
         "test.category"));
   }
 
   scoped_refptr<MockTimeDomain> time_domain_;
   scoped_refptr<internal::TaskQueueImpl> task_queue_;
 };
 
 TEST_F(TimeDomainTest, ScheduleDelayedWork) {
   base::TimeDelta delay = base::TimeDelta::FromMilliseconds(10);
   base::TimeTicks delayed_runtime = time_domain_->Now() + delay;
-  EXPECT_CALL(*time_domain_.get(), RequestWakeup(delay));
+  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_, delay));
   LazyNow lazy_now = time_domain_->CreateLazyNow();
   time_domain_->ScheduleDelayedWork(task_queue_.get(),
                                     time_domain_->Now() + delay, &lazy_now);
 
   base::TimeTicks next_scheduled_runtime;
   EXPECT_TRUE(time_domain_->NextScheduledRunTime(&next_scheduled_runtime));
   EXPECT_EQ(delayed_runtime, next_scheduled_runtime);
 
   TaskQueue* next_task_queue;
   EXPECT_TRUE(time_domain_->NextScheduledTaskQueue(&next_task_queue));
   EXPECT_EQ(task_queue_.get(), next_task_queue);
 }
 
+TEST_F(TimeDomainTest, RequestWakeup_OnlyCalledForEarlierTasks) {
+  base::TimeDelta delay1 = base::TimeDelta::FromMilliseconds(10);
+  base::TimeDelta delay2 = base::TimeDelta::FromMilliseconds(20);
+  base::TimeDelta delay3 = base::TimeDelta::FromMilliseconds(30);
+  base::TimeDelta delay4 = base::TimeDelta::FromMilliseconds(1);
+
+  // RequestWakeup should always be called if there are no other wakeups.
+  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_, delay1));
+  LazyNow lazy_now = time_domain_->CreateLazyNow();
+  time_domain_->ScheduleDelayedWork(task_queue_.get(),
+                                    time_domain_->Now() + delay1, &lazy_now);
+
+  Mock::VerifyAndClearExpectations(time_domain_.get());
+
+  // RequestWakeup should not be called when scheduling later tasks.
+  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_, _)).Times(0);
+  time_domain_->ScheduleDelayedWork(task_queue_.get(),
+                                    time_domain_->Now() + delay2, &lazy_now);
+  time_domain_->ScheduleDelayedWork(task_queue_.get(),
+                                    time_domain_->Now() + delay3, &lazy_now);
+
+  // RequestWakeup should be called when scheduling earlier tasks.
+  Mock::VerifyAndClearExpectations(time_domain_.get());
+  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_, delay4));
+  time_domain_->ScheduleDelayedWork(task_queue_.get(),
+                                    time_domain_->Now() + delay4, &lazy_now);
+}
+
 TEST_F(TimeDomainTest, UnregisterQueue) {
   scoped_refptr<internal::TaskQueueImpl> task_queue2_ =
       make_scoped_refptr(new internal::TaskQueueImpl(
           nullptr, time_domain_, TaskQueue::Spec("test_queue2"),
           "test.category", "test.category"));
 
-  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_)).Times(2);
+  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_, _)).Times(1);
   LazyNow lazy_now = time_domain_->CreateLazyNow();
   time_domain_->ScheduleDelayedWork(
       task_queue_.get(),
       time_domain_->Now() + base::TimeDelta::FromMilliseconds(10), &lazy_now);
   time_domain_->ScheduleDelayedWork(
       task_queue2_.get(),
       time_domain_->Now() + base::TimeDelta::FromMilliseconds(100), &lazy_now);
 
   TaskQueue* next_task_queue;
   EXPECT_TRUE(time_domain_->NextScheduledTaskQueue(&next_task_queue));
@@ skipping 24 matching lines @@
   // next time MoveReadyDelayedTasksToIncomingQueue is called, the task will
   // get moved onto the incomming queue.
   base::TimeDelta dummy_delay = base::TimeDelta::FromMilliseconds(10);
   dummy_queue->PostDelayedTask(FROM_HERE, base::Closure(), dummy_delay);
   dummy_time_source.Advance(dummy_delay);
 
   // Now we can test that ScheduleDelayedWork triggers calls to
   // MoveReadyDelayedTasksToIncomingQueue as expected.
   base::TimeDelta delay = base::TimeDelta::FromMilliseconds(50);
   base::TimeTicks delayed_runtime = time_domain_->Now() + delay;
-  EXPECT_CALL(*time_domain_.get(), RequestWakeup(delay));
+  EXPECT_CALL(*time_domain_.get(), RequestWakeup(_, delay));
   LazyNow lazy_now = time_domain_->CreateLazyNow();
   time_domain_->ScheduleDelayedWork(dummy_queue.get(), delayed_runtime,
                                     &lazy_now);
 
   time_domain_->UpdateWorkQueues(false, nullptr);
   EXPECT_EQ(0UL, dummy_queue->IncomingQueueSizeForTest());
 
   time_domain_->SetNow(delayed_runtime);
   time_domain_->UpdateWorkQueues(false, nullptr);
   EXPECT_EQ(1UL, dummy_queue->IncomingQueueSizeForTest());
 }
 
 }  // namespace scheduler