Handle delayed tasks more natively in the scheduler

content/renderer/scheduler/task_queue_manager_unittest.cc

Index: content/renderer/scheduler/task_queue_manager_unittest.cc
diff --git a/content/renderer/scheduler/task_queue_manager_unittest.cc b/content/renderer/scheduler/task_queue_manager_unittest.cc
index 845e9bad2c4e7e1bdb27d819b1c20774483338db..99c054ba6ad73e0f4098d7d566fc246b17db6761 100644
--- a/content/renderer/scheduler/task_queue_manager_unittest.cc
+++ b/content/renderer/scheduler/task_queue_manager_unittest.cc
@@ -4,8 +4,8 @@
 
 #include "content/renderer/scheduler/task_queue_manager.h"
 
-#include "base/test/test_simple_task_runner.h"
 #include "base/threading/thread.h"
+#include "cc/test/ordered_simple_task_runner.h"
 #include "cc/test/test_now_source.h"
 #include "content/renderer/scheduler/nestable_task_runner_for_test.h"
 #include "content/renderer/scheduler/renderer_scheduler_message_loop_delegate.h"
@@ -56,11 +56,15 @@ class SelectorForTest : public TaskQueueSelector {
 class TaskQueueManagerTest : public testing::Test {
  protected:
   void Initialize(size_t num_queues) {
-    test_task_runner_ = make_scoped_refptr(new base::TestSimpleTaskRunner());
+    now_src_ = cc::TestNowSource::Create(1000);
+    test_task_runner_ =
+        make_scoped_refptr(new cc::OrderedSimpleTaskRunner(now_src_, false));
     selector_ = make_scoped_ptr(new SelectorForTest);
     manager_ = make_scoped_ptr(new TaskQueueManager(
         num_queues, NestableTaskRunnerForTest::Create(test_task_runner_.get()),
         selector_.get()));
+    manager_->SetTimeSourceForTesting(now_src_);
+
     EXPECT_EQ(num_queues, selector_->work_queues().size());
   }
 
@@ -74,7 +78,8 @@ class TaskQueueManagerTest : public testing::Test {
     EXPECT_EQ(num_queues, selector_->work_queues().size());
   }
 
-  scoped_refptr<base::TestSimpleTaskRunner> test_task_runner_;
+  scoped_refptr<cc::TestNowSource> now_src_;
+  scoped_refptr<cc::OrderedSimpleTaskRunner> test_task_runner_;
   scoped_ptr<SelectorForTest> selector_;
   scoped_ptr<TaskQueueManager> manager_;
   scoped_ptr<base::MessageLoop> message_loop_;
@@ -144,6 +149,39 @@ TEST_F(TaskQueueManagerTest, MultiQueuePosting) {
   EXPECT_THAT(run_order, ElementsAre(1, 3, 5, 2, 4, 6));
 }
 
+void NopTask() {
+}
+
+TEST_F(TaskQueueManagerTest, NowNotCalledWhenThereAreNoDelayedTasks) {
+  Initialize(3u);
+
+  scoped_refptr<cc::TestNowSource> now_src = cc::TestNowSource::Create(1000);
+  manager_->SetTimeSourceForTesting(now_src);
+
+  scoped_refptr<base::SingleThreadTaskRunner> runners[3] = {
+      manager_->TaskRunnerForQueue(0),
+      manager_->TaskRunnerForQueue(1),
+      manager_->TaskRunnerForQueue(2)};
+
+  selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(1);
+  selector_->AppendQueueToService(2);
+  selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(1);
+  selector_->AppendQueueToService(2);
+
+  runners[0]->PostTask(FROM_HERE, base::Bind(&NopTask));
+  runners[0]->PostTask(FROM_HERE, base::Bind(&NopTask));
+  runners[1]->PostTask(FROM_HERE, base::Bind(&NopTask));
+  runners[1]->PostTask(FROM_HERE, base::Bind(&NopTask));
+  runners[2]->PostTask(FROM_HERE, base::Bind(&NopTask));
+  runners[2]->PostTask(FROM_HERE, base::Bind(&NopTask));
+
+  test_task_runner_->RunUntilIdle();
+
+  EXPECT_EQ(0, now_src->NumNowCalls());
+}
+
 TEST_F(TaskQueueManagerTest, NonNestableTaskPosting) {
   InitializeWithRealMessageLoop(1u);
 
@@ -245,22 +283,20 @@ TEST_F(TaskQueueManagerTest, DelayedTaskPosting) {
   base::TimeDelta delay(base::TimeDelta::FromMilliseconds(10));
   runner->PostDelayedTask(
       FROM_HERE, base::Bind(&TestTask, 1, &run_order), delay);
-  EXPECT_EQ(delay, test_task_runner_->NextPendingTaskDelay());
+  EXPECT_EQ(delay, test_task_runner_->DelayToNextTaskTime());
   EXPECT_TRUE(manager_->IsQueueEmpty(0));
   EXPECT_TRUE(run_order.empty());
 
-  // The task is inserted to the incoming queue only after the delay.
-  test_task_runner_->RunPendingTasks();
-  EXPECT_FALSE(manager_->IsQueueEmpty(0));
+  // The task doesn't run before the delay has completed.
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(9));
   EXPECT_TRUE(run_order.empty());
 
-  // After the delay the task runs normally.
-  selector_->AppendQueueToService(0);
-  test_task_runner_->RunUntilIdle();
+  // After the delay has completed, the task runs normally.
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(1));
   EXPECT_THAT(run_order, ElementsAre(1));
 }
 
-TEST_F(TaskQueueManagerTest, DelayedTaskDoesNotStayDelayed) {
+TEST_F(TaskQueueManagerTest, DelayedTaskPosting_MultipleTasks) {
   Initialize(1u);
 
   std::vector<int> run_order;
@@ -268,21 +304,80 @@ TEST_F(TaskQueueManagerTest, DelayedTaskDoesNotStayDelayed) {
       manager_->TaskRunnerForQueue(0);
 
   selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(0);
+
+  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order),
+                          base::TimeDelta::FromMilliseconds(10));
+
+  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 2, &run_order),
+                          base::TimeDelta::FromMilliseconds(8));
+
+  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 3, &run_order),
+                          base::TimeDelta::FromMilliseconds(5));
+
+  EXPECT_EQ(base::TimeDelta::FromMilliseconds(5),
+            test_task_runner_->DelayToNextTaskTime());
+
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(5));
+  EXPECT_THAT(run_order, ElementsAre(3));
+  EXPECT_EQ(base::TimeDelta::FromMilliseconds(3),
+            test_task_runner_->DelayToNextTaskTime());
+
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(3));
+  EXPECT_THAT(run_order, ElementsAre(3, 2));
+  EXPECT_EQ(base::TimeDelta::FromMilliseconds(2),
+            test_task_runner_->DelayToNextTaskTime());
+
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(2));
+  EXPECT_THAT(run_order, ElementsAre(3, 2, 1));
+}
+
+TEST_F(TaskQueueManagerTest, PostDelayedTask_SharesUnderlyingDelayedTasks) {
+  Initialize(1u);
+
+  std::vector<int> run_order;
+  scoped_refptr<base::SingleThreadTaskRunner> runner =
+      manager_->TaskRunnerForQueue(0);
 
   base::TimeDelta delay(base::TimeDelta::FromMilliseconds(10));
   runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order),
                           delay);
-  test_task_runner_->RunPendingTasks();
+  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 2, &run_order),
+                          delay);
+  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 3, &run_order),
+                          delay);
 
-  // Reload the work queue so we see the next pending task. It should no longer
-  // be marked as delayed.
-  manager_->PumpQueue(0);
-  EXPECT_TRUE(selector_->work_queues()[0]->front().delayed_run_time.is_null());
+  EXPECT_EQ(1u, test_task_runner_->NumPendingTasks());
+}
 
-  // Let the task run normally.
-  selector_->AppendQueueToService(0);
-  test_task_runner_->RunUntilIdle();
-  EXPECT_THAT(run_order, ElementsAre(1));
+class TestObject {
+ public:
+  ~TestObject() { destructor_count_++; }
+
+  void Run() { FAIL() << "TestObject::Run should not be called"; }
+
+  static int destructor_count_;
+};
+
+int TestObject::destructor_count_ = 0;
+
+TEST_F(TaskQueueManagerTest, PendingDelayedTasksRemovedOnShutdown) {
+  Initialize(1u);
+
+  TestObject::destructor_count_ = 0;
+
+  scoped_refptr<base::SingleThreadTaskRunner> runner =
+      manager_->TaskRunnerForQueue(0);
+
+  base::TimeDelta delay(base::TimeDelta::FromMilliseconds(10));
+  runner->PostDelayedTask(
+      FROM_HERE, base::Bind(&TestObject::Run, base::Owned(new TestObject())),
+      delay);
+
+  manager_.reset();
+
+  EXPECT_EQ(1, TestObject::destructor_count_);
 }
 
 TEST_F(TaskQueueManagerTest, ManualPumping) {
@@ -296,14 +391,14 @@ TEST_F(TaskQueueManagerTest, ManualPumping) {
   // Posting a task when pumping is disabled doesn't result in work getting
   // posted.
   runner->PostTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order));
-  EXPECT_FALSE(test_task_runner_->HasPendingTask());
+  EXPECT_FALSE(test_task_runner_->HasPendingTasks());
 
   // However polling still works.
   EXPECT_FALSE(manager_->IsQueueEmpty(0));
 
   // After pumping the task runs normally.
   manager_->PumpQueue(0);
-  EXPECT_TRUE(test_task_runner_->HasPendingTask());
+  EXPECT_TRUE(test_task_runner_->HasPendingTasks());
   selector_->AppendQueueToService(0);
   test_task_runner_->RunUntilIdle();
   EXPECT_THAT(run_order, ElementsAre(1));
@@ -320,11 +415,11 @@ TEST_F(TaskQueueManagerTest, ManualPumpingToggle) {
   // Posting a task when pumping is disabled doesn't result in work getting
   // posted.
   runner->PostTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order));
-  EXPECT_FALSE(test_task_runner_->HasPendingTask());
+  EXPECT_FALSE(test_task_runner_->HasPendingTasks());
 
   // When pumping is enabled the task runs normally.
   manager_->SetPumpPolicy(0, TaskQueueManager::PumpPolicy::AUTO);
-  EXPECT_TRUE(test_task_runner_->HasPendingTask());
+  EXPECT_TRUE(test_task_runner_->HasPendingTasks());
   selector_->AppendQueueToService(0);
   test_task_runner_->RunUntilIdle();
   EXPECT_THAT(run_order, ElementsAre(1));
@@ -357,21 +452,74 @@ TEST_F(TaskQueueManagerTest, ManualPumpingWithDelayedTask) {
   std::vector<int> run_order;
   scoped_refptr<base::SingleThreadTaskRunner> runner =
       manager_->TaskRunnerForQueue(0);
+  selector_->AppendQueueToService(0);
 
   // Posting a delayed task when pumping will apply the delay, but won't cause
   // work to executed afterwards.
   base::TimeDelta delay(base::TimeDelta::FromMilliseconds(10));
   runner->PostDelayedTask(
       FROM_HERE, base::Bind(&TestTask, 1, &run_order), delay);
-  test_task_runner_->RunUntilIdle();
+
+  // After pumping but before the delay period has expired, task does not run.
+  manager_->PumpQueue(0);
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(5));
   EXPECT_TRUE(run_order.empty());
 
-  // After pumping the task runs normally.
+  // Once the delay has expired, pumping causes the task to run.
+  now_src_->AdvanceNow(base::TimeDelta::FromMilliseconds(5));
   manager_->PumpQueue(0);
-  EXPECT_TRUE(test_task_runner_->HasPendingTask());
+  EXPECT_TRUE(test_task_runner_->HasPendingTasks());
+  test_task_runner_->RunPendingTasks();
+  EXPECT_THAT(run_order, ElementsAre(1));
+}
+
+TEST_F(TaskQueueManagerTest, ManualPumpingWithMultipleDelayedTasks) {
+  Initialize(1u);
+  manager_->SetPumpPolicy(0, TaskQueueManager::PumpPolicy::MANUAL);
+
+  std::vector<int> run_order;
+  scoped_refptr<base::SingleThreadTaskRunner> runner =
+      manager_->TaskRunnerForQueue(0);
   selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(0);
+
+  // Posting a delayed task when pumping will apply the delay, but won't cause
+  // work to executed afterwards.
+  base::TimeDelta delay1(base::TimeDelta::FromMilliseconds(1));
+  base::TimeDelta delay2(base::TimeDelta::FromMilliseconds(10));
+  base::TimeDelta delay3(base::TimeDelta::FromMilliseconds(20));
+  runner->PostDelayedTask(
+      FROM_HERE, base::Bind(&TestTask, 1, &run_order), delay1);
+  runner->PostDelayedTask(
+      FROM_HERE, base::Bind(&TestTask, 2, &run_order), delay2);
+  runner->PostDelayedTask(
+      FROM_HERE, base::Bind(&TestTask, 3, &run_order), delay3);
+
+  now_src_->AdvanceNow(base::TimeDelta::FromMilliseconds(15));
   test_task_runner_->RunUntilIdle();
-  EXPECT_THAT(run_order, ElementsAre(1));
+  EXPECT_TRUE(run_order.empty());
+
+  // Once the delay has expired, pumping causes the task to run.
+  manager_->PumpQueue(0);
+  test_task_runner_->RunUntilIdle();
+  EXPECT_THAT(run_order, ElementsAre(1, 2));
+}
+
+TEST_F(TaskQueueManagerTest, DelayedTasksDontAutoRunWithManualPumping) {
+  Initialize(1u);
+  manager_->SetPumpPolicy(0, TaskQueueManager::PumpPolicy::MANUAL);
+
+  std::vector<int> run_order;
+  scoped_refptr<base::SingleThreadTaskRunner> runner =
+      manager_->TaskRunnerForQueue(0);
+  selector_->AppendQueueToService(0);
+
+  base::TimeDelta delay(base::TimeDelta::FromMilliseconds(10));
+  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order),
+                          delay);
+
+  test_task_runner_->RunForPeriod(base::TimeDelta::FromMilliseconds(10));
+  EXPECT_TRUE(run_order.empty());
 }
 
 TEST_F(TaskQueueManagerTest, ManualPumpingWithNonEmptyWorkQueue) {
@@ -482,7 +630,7 @@ TEST_F(TaskQueueManagerTest, DoWorkCantPostItselfMultipleTimes) {
   test_task_runner_->RunPendingTasks();
   // NOTE without the executing_task_ check in MaybePostDoWorkOnMainRunner there
   // will be two tasks here.
-  EXPECT_EQ(1u, test_task_runner_->GetPendingTasks().size());
+  EXPECT_EQ(1u, test_task_runner_->NumPendingTasks());
   EXPECT_EQ(1, run_count);
 }
 
@@ -534,61 +682,16 @@ TEST_F(TaskQueueManagerTest, WorkBatching) {
 
   // Running one task in the host message loop should cause two posted tasks to
   // get executed.
-  EXPECT_EQ(test_task_runner_->GetPendingTasks().size(), 1u);
+  EXPECT_EQ(test_task_runner_->NumPendingTasks(), 1u);
   test_task_runner_->RunPendingTasks();
   EXPECT_THAT(run_order, ElementsAre(1, 2));
 
   // The second task runs the remaining two posted tasks.
-  EXPECT_EQ(test_task_runner_->GetPendingTasks().size(), 1u);
+  EXPECT_EQ(test_task_runner_->NumPendingTasks(), 1u);
   test_task_runner_->RunPendingTasks();
   EXPECT_THAT(run_order, ElementsAre(1, 2, 3, 4));
 }
 
-void AdvanceNowTestTask(int value,
-                        std::vector<int>* out_result,
-                        scoped_refptr<cc::TestNowSource> time_source,
-                        base::TimeDelta delta) {
-  TestTask(value, out_result);
-  time_source->AdvanceNow(delta);
-}
-
-TEST_F(TaskQueueManagerTest, InterruptWorkBatchForDelayedTask) {
-  scoped_refptr<cc::TestNowSource> clock(cc::TestNowSource::Create());
-  Initialize(1u);
-
-  manager_->SetWorkBatchSize(2);
-  manager_->SetTimeSourceForTesting(clock);
-
-  std::vector<int> run_order;
-  scoped_refptr<base::SingleThreadTaskRunner> runner =
-      manager_->TaskRunnerForQueue(0);
-
-  selector_->AppendQueueToService(0);
-  selector_->AppendQueueToService(0);
-  selector_->AppendQueueToService(0);
-
-  base::TimeDelta delta(base::TimeDelta::FromMilliseconds(10));
-  runner->PostTask(
-      FROM_HERE, base::Bind(&AdvanceNowTestTask, 2, &run_order, clock, delta));
-  runner->PostTask(
-      FROM_HERE, base::Bind(&AdvanceNowTestTask, 3, &run_order, clock, delta));
-
-  base::TimeDelta delay(base::TimeDelta::FromMilliseconds(5));
-  runner->PostDelayedTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order),
-                          delay);
-
-  // At this point we have two posted tasks: one for DoWork and one of the
-  // delayed task. Only the first non-delayed task should get executed because
-  // the work batch is interrupted by the pending delayed task.
-  EXPECT_EQ(test_task_runner_->GetPendingTasks().size(), 2u);
-  test_task_runner_->RunPendingTasks();
-  EXPECT_THAT(run_order, ElementsAre(2));
-
-  // Running all remaining tasks should execute both pending tasks.
-  test_task_runner_->RunUntilIdle();
-  EXPECT_THAT(run_order, ElementsAre(2, 3, 1));
-}
-
 TEST_F(TaskQueueManagerTest, AutoPumpAfterWakeup) {
   Initialize(2u);
   manager_->SetPumpPolicy(0, TaskQueueManager::PumpPolicy::AFTER_WAKEUP);
@@ -725,9 +828,6 @@ TEST_F(TaskQueueManagerTest, AutoPumpAfterWakeupFromMultipleTasks) {
   EXPECT_THAT(run_order, ElementsAre(3, 1, 2));
 }
 
-void NullTestTask() {
-}
-
 TEST_F(TaskQueueManagerTest, AutoPumpAfterWakeupBecomesQuiescent) {
   Initialize(2u);
   manager_->SetPumpPolicy(0, TaskQueueManager::PumpPolicy::AFTER_WAKEUP);
@@ -751,7 +851,7 @@ TEST_F(TaskQueueManagerTest, AutoPumpAfterWakeupBecomesQuiescent) {
                        base::Bind(&RePostingTestTask, runners[0], &run_count));
   runners[0]->PostTask(FROM_HERE,
                        base::Bind(&RePostingTestTask, runners[0], &run_count));
-  runners[1]->PostTask(FROM_HERE, base::Bind(&NullTestTask));
+  runners[1]->PostTask(FROM_HERE, base::Bind(&NopTask));
   test_task_runner_->RunUntilIdle();
   // The reposting tasks posted to the after wakeup queue shouldn't have woken
   // each other up.