Introduce a SchedulerHelper in content/child/scheduler

content/child/scheduler/scheduler_helper_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 "content/renderer/scheduler/renderer_scheduler_impl.h"
+#include "content/child/scheduler/scheduler_helper.h"
 
 #include "base/callback.h"
-#include "cc/output/begin_frame_args.h"
 #include "cc/test/ordered_simple_task_runner.h"
-#include "content/renderer/scheduler/nestable_task_runner_for_test.h"
-#include "content/renderer/scheduler/renderer_scheduler_message_loop_delegate.h"
+#include "content/child/scheduler/nestable_task_runner_for_test.h"
+#include "content/child/scheduler/scheduler_message_loop_delegate.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+using testing::_;
+using testing::Invoke;
+using testing::Return;
+
 namespace content {
 
 namespace {
-class FakeInputEvent : public blink::WebInputEvent {
- public:
-  explicit FakeInputEvent(blink::WebInputEvent::Type event_type)
-      : WebInputEvent(sizeof(FakeInputEvent)) {
-    type = event_type;
-  }
-
-  FakeInputEvent(blink::WebInputEvent::Type event_type, int event_modifiers)
-      : WebInputEvent(sizeof(FakeInputEvent)) {
-    type = event_type;
-    modifiers = event_modifiers;
-  }
-};
-
 void AppendToVectorTestTask(std::vector<std::string>* vector,
                             std::string value) {
   vector->push_back(value);
 }
 
 void AppendToVectorIdleTestTask(std::vector<std::string>* vector,
                                 std::string value,
                                 base::TimeTicks deadline) {
   AppendToVectorTestTask(vector, value);
 }
 
+void NullTask() {
+}
+
+void AppendToVectorReentrantTask(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+    std::vector<int>* vector,
+    int* reentrant_count,
+    int max_reentrant_count) {
+  vector->push_back((*reentrant_count)++);
+  if (*reentrant_count < max_reentrant_count) {
+    task_runner->PostTask(
+        FROM_HERE, base::Bind(AppendToVectorReentrantTask, task_runner, vector,
+                              reentrant_count, max_reentrant_count));
+  }
+}
+
+void IdleTestTask(int* run_count,
+                  base::TimeTicks* deadline_out,
+                  base::TimeTicks deadline) {
+  (*run_count)++;
+  *deadline_out = deadline;
+}
+
+int max_idle_task_reposts = 2;
+
+void RepostingIdleTestTask(
+    scoped_refptr<SingleThreadIdleTaskRunner> idle_task_runner,
+    int* run_count,
+    base::TimeTicks deadline) {
+  if ((*run_count + 1) < max_idle_task_reposts) {
+    idle_task_runner->PostIdleTask(
+        FROM_HERE,
+        base::Bind(&RepostingIdleTestTask, idle_task_runner, run_count));
+  }
+  (*run_count)++;
+}
+
 };  // namespace
 
-class RendererSchedulerImplTest : public testing::Test {
+class SchedulerHelperForTest : public SchedulerHelper,
+                               public SchedulerHelper::SchedulerHelperDelegate {
  public:
-  using Policy = RendererSchedulerImpl::Policy;
+  explicit SchedulerHelperForTest(
+      scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner)
+      : SchedulerHelper(main_task_runner,
+                        this,
+                        "test.scheduler",
+                        TRACE_DISABLED_BY_DEFAULT("test.scheduler"),
+                        TASK_QUEUE_COUNT) {}
 
-  RendererSchedulerImplTest()
+  ~SchedulerHelperForTest() override {}
+
+  using IdlePeriodState = SchedulerHelper::IdlePeriodState;
+  using SchedulerHelper::CanExceedIdleDeadlineIfRequired;
+  using SchedulerHelper::EndIdlePeriod;
+  using SchedulerHelper::StartIdlePeriod;
+  using SchedulerHelper::InitiateLongIdlePeriod;
+  using SchedulerHelper::EstimatedEndOfIdle;
+
+  // SchedulerHelperDelegate implementation:
+  MOCK_METHOD2(CanEnterLongIdlePeriod,
+               bool(base::TimeTicks now,
+                    base::TimeDelta* next_long_idle_period_delay_out));
+};
+
+class SchedulerHelperTest : public testing::Test {
+ public:
+  SchedulerHelperTest()
       : clock_(cc::TestNowSource::Create(5000)),
         mock_task_runner_(new cc::OrderedSimpleTaskRunner(clock_, false)),
         nestable_task_runner_(
             NestableTaskRunnerForTest::Create(mock_task_runner_)),
-        scheduler_(new RendererSchedulerImpl(nestable_task_runner_)),
-        default_task_runner_(scheduler_->DefaultTaskRunner()),
-        compositor_task_runner_(scheduler_->CompositorTaskRunner()),
-        loading_task_runner_(scheduler_->LoadingTaskRunner()),
-        idle_task_runner_(scheduler_->IdleTaskRunner()) {
-    scheduler_->SetTimeSourceForTesting(clock_);
+        scheduler_helper_(new SchedulerHelperForTest(nestable_task_runner_)),
+        default_task_runner_(scheduler_helper_->DefaultTaskRunner()),
+        idle_task_runner_(scheduler_helper_->IdleTaskRunner()) {
+    scheduler_helper_->SetTimeSourceForTesting(clock_);
   }
 
-  RendererSchedulerImplTest(base::MessageLoop* message_loop)
+  SchedulerHelperTest(base::MessageLoop* message_loop)
       : clock_(cc::TestNowSource::Create(5000)),
         message_loop_(message_loop),
         nestable_task_runner_(
-            RendererSchedulerMessageLoopDelegate::Create(message_loop)),
-        scheduler_(new RendererSchedulerImpl(nestable_task_runner_)),
-        default_task_runner_(scheduler_->DefaultTaskRunner()),
-        compositor_task_runner_(scheduler_->CompositorTaskRunner()),
-        loading_task_runner_(scheduler_->LoadingTaskRunner()),
-        idle_task_runner_(scheduler_->IdleTaskRunner()) {
-    scheduler_->SetTimeSourceForTesting(clock_);
+            SchedulerMessageLoopDelegate::Create(message_loop)),
+        scheduler_helper_(new SchedulerHelperForTest(nestable_task_runner_)),
+        default_task_runner_(scheduler_helper_->DefaultTaskRunner()),
+        idle_task_runner_(scheduler_helper_->IdleTaskRunner()) {
+    scheduler_helper_->SetTimeSourceForTesting(clock_);
   }
-  ~RendererSchedulerImplTest() override {}
+  ~SchedulerHelperTest() override {}
 
   void TearDown() override {
     DCHECK(!mock_task_runner_.get() || !message_loop_.get());
     if (mock_task_runner_.get()) {
       // Check that all tests stop posting tasks.
       mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
       while (mock_task_runner_->RunUntilIdle()) {
       }
     } else {
       message_loop_->RunUntilIdle();
     }
   }
 
   void RunUntilIdle() {
     // Only one of mock_task_runner_ or message_loop_ should be set.
     DCHECK(!mock_task_runner_.get() || !message_loop_.get());
     if (mock_task_runner_.get())
       mock_task_runner_->RunUntilIdle();
     else
       message_loop_->RunUntilIdle();
   }
 
-  void DoMainFrame() {
-    scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-        BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-        base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
-    scheduler_->DidCommitFrameToCompositor();
-  }
-
-  void EnableIdleTasks() { DoMainFrame(); }
-
-  Policy CurrentPolicy() { return scheduler_->current_policy_; }
-
-  void EnsureUrgentPolicyUpdatePostedOnMainThread() {
-    base::AutoLock lock(scheduler_->incoming_signals_lock_);
-    scheduler_->EnsureUrgentPolicyUpdatePostedOnMainThread(FROM_HERE);
-  }
-
-  void ScheduleDelayedPolicyUpdate(base::TimeDelta delay) {
-    scheduler_->delayed_update_policy_runner_.SetDeadline(FROM_HERE, delay,
-                                                          clock_->Now());
-  }
-
   // Helper for posting several tasks of specific types. |task_descriptor| is a
   // string with space delimited task identifiers. The first letter of each
   // task identifier specifies the task type:
   // - 'D': Default task
-  // - 'C': Compositor task
-  // - 'L': Loading task
   // - 'I': Idle task
   void PostTestTasks(std::vector<std::string>* run_order,
                      const std::string& task_descriptor) {
     std::istringstream stream(task_descriptor);
     while (!stream.eof()) {
       std::string task;
       stream >> task;
       switch (task[0]) {
         case 'D':
           default_task_runner_->PostTask(
               FROM_HERE, base::Bind(&AppendToVectorTestTask, run_order, task));
           break;
-        case 'C':
-          compositor_task_runner_->PostTask(
-              FROM_HERE, base::Bind(&AppendToVectorTestTask, run_order, task));
-          break;
-        case 'L':
-          loading_task_runner_->PostTask(
-              FROM_HERE, base::Bind(&AppendToVectorTestTask, run_order, task));
-          break;
         case 'I':
           idle_task_runner_->PostIdleTask(
               FROM_HERE,
               base::Bind(&AppendToVectorIdleTestTask, run_order, task));
           break;
         default:
           NOTREACHED();
       }
     }
   }
 
  protected:
-  static base::TimeDelta priority_escalation_after_input_duration() {
+  static base::TimeDelta maximum_idle_period_duration() {
     return base::TimeDelta::FromMilliseconds(
-        RendererSchedulerImpl::kPriorityEscalationAfterInputMillis);
+        SchedulerHelper::kMaximumIdlePeriodMillis);
   }
 
-  static base::TimeDelta maximum_idle_period_duration() {
-    return base::TimeDelta::FromMilliseconds(
-        RendererSchedulerImpl::kMaximumIdlePeriodMillis);
-  }
-
-  base::TimeTicks CurrentIdleTaskDeadline() {
+  base::TimeTicks CurrentIdleTaskDeadlineForTesting() {
     base::TimeTicks deadline;
-    scheduler_->CurrentIdleTaskDeadlineCallback(&deadline);
+    scheduler_helper_->CurrentIdleTaskDeadlineCallback(&deadline);
     return deadline;
   }
 
   scoped_refptr<cc::TestNowSource> clock_;
   // Only one of mock_task_runner_ or message_loop_ will be set.
   scoped_refptr<cc::OrderedSimpleTaskRunner> mock_task_runner_;
   scoped_ptr<base::MessageLoop> message_loop_;
 
   scoped_refptr<NestableSingleThreadTaskRunner> nestable_task_runner_;
-  scoped_ptr<RendererSchedulerImpl> scheduler_;
+  scoped_ptr<SchedulerHelperForTest> scheduler_helper_;
   scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
-  scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;
-  scoped_refptr<base::SingleThreadTaskRunner> loading_task_runner_;
   scoped_refptr<SingleThreadIdleTaskRunner> idle_task_runner_;
 
-  DISALLOW_COPY_AND_ASSIGN(RendererSchedulerImplTest);
+  DISALLOW_COPY_AND_ASSIGN(SchedulerHelperTest);
 };
 
-void NullTask() {
-}
-
-void AppendToVectorReentrantTask(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    std::vector<int>* vector,
-    int* reentrant_count,
-    int max_reentrant_count) {
-  vector->push_back((*reentrant_count)++);
-  if (*reentrant_count < max_reentrant_count) {
-    task_runner->PostTask(
-        FROM_HERE, base::Bind(AppendToVectorReentrantTask, task_runner, vector,
-                              reentrant_count, max_reentrant_count));
-  }
-}
-
-void IdleTestTask(int* run_count,
-                  base::TimeTicks* deadline_out,
-                  base::TimeTicks deadline) {
-  (*run_count)++;
-  *deadline_out = deadline;
-}
-
-void RepostingIdleTestTask(
-    scoped_refptr<SingleThreadIdleTaskRunner> idle_task_runner,
-    int* run_count,
-    base::TimeTicks deadline) {
-  if (*run_count == 0) {
-    idle_task_runner->PostIdleTask(
-        FROM_HERE,
-        base::Bind(&RepostingIdleTestTask, idle_task_runner, run_count));
-  }
-  (*run_count)++;
-}
-
-void UpdateClockToDeadlineIdleTestTask(
-    scoped_refptr<cc::TestNowSource> clock,
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    int* run_count,
-    base::TimeTicks deadline) {
-  clock->SetNow(deadline);
-  // Due to the way in which OrderedSimpleTestRunner orders tasks and the fact
-  // that we updated the time within a task, the delayed pending task to call
-  // EndIdlePeriod will not happen until after a TaskQueueManager DoWork, so
-  // post a normal task here to ensure it runs before the next idle task.
-  task_runner->PostTask(FROM_HERE, base::Bind(NullTask));
-  (*run_count)++;
-}
-
-void PostingYieldingTestTask(
-    RendererSchedulerImpl* scheduler,
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    bool simulate_input,
-    bool* should_yield_before,
-    bool* should_yield_after) {
-  *should_yield_before = scheduler->ShouldYieldForHighPriorityWork();
-  task_runner->PostTask(FROM_HERE, base::Bind(NullTask));
-  if (simulate_input) {
-    scheduler->DidReceiveInputEventOnCompositorThread(
-        FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  }
-  *should_yield_after = scheduler->ShouldYieldForHighPriorityWork();
-}
-
-void AnticipationTestTask(RendererSchedulerImpl* scheduler,
-                          bool simulate_input,
-                          bool* is_anticipated_before,
-                          bool* is_anticipated_after) {
-  *is_anticipated_before = scheduler->IsHighPriorityWorkAnticipated();
-  if (simulate_input) {
-    scheduler->DidReceiveInputEventOnCompositorThread(
-        FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  }
-  *is_anticipated_after = scheduler->IsHighPriorityWorkAnticipated();
-}
-
-TEST_F(RendererSchedulerImplTest, TestPostDefaultTask) {
+TEST_F(SchedulerHelperTest, TestPostDefaultTask) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "D1 D2 D3 D4");
 
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("D1"), std::string("D2"),
                                    std::string("D3"), std::string("D4")));
 }
 
-TEST_F(RendererSchedulerImplTest, TestPostDefaultAndCompositor) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "D1 C1");
-  RunUntilIdle();
-  EXPECT_THAT(run_order, testing::Contains("D1"));
-  EXPECT_THAT(run_order, testing::Contains("C1"));
-}
-
-TEST_F(RendererSchedulerImplTest, TestRentrantTask) {
+TEST_F(SchedulerHelperTest, TestRentrantTask) {
   int count = 0;
   std::vector<int> run_order;
   default_task_runner_->PostTask(
       FROM_HERE, base::Bind(AppendToVectorReentrantTask, default_task_runner_,
                             &run_order, &count, 5));
   RunUntilIdle();
 
   EXPECT_THAT(run_order, testing::ElementsAre(0, 1, 2, 3, 4));
 }
 
-TEST_F(RendererSchedulerImplTest, TestPostIdleTask) {
+TEST_F(SchedulerHelperTest, TestPostIdleTask) {
   int run_count = 0;
   base::TimeTicks expected_deadline =
       clock_->Now() + base::TimeDelta::FromMilliseconds(2300);
+  scheduler_helper_->SetEstimatedEndOfIdle(expected_deadline);
   base::TimeTicks deadline_in_task;
 
   clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(100));
   idle_task_runner_->PostIdleTask(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
 
   RunUntilIdle();
-  EXPECT_EQ(0, run_count);  // Shouldn't run yet as no WillBeginFrame.
+  EXPECT_EQ(0, run_count);
 
-  scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
-  RunUntilIdle();
-  EXPECT_EQ(0, run_count);  // Shouldn't run as no DidCommitFrameToCompositor.
-
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(1200));
-  scheduler_->DidCommitFrameToCompositor();
-  RunUntilIdle();
-  EXPECT_EQ(0, run_count);  // We missed the deadline.
-
-  scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(800));
-  scheduler_->DidCommitFrameToCompositor();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   EXPECT_EQ(1, run_count);
   EXPECT_EQ(expected_deadline, deadline_in_task);
 }
 
-TEST_F(RendererSchedulerImplTest, TestRepostingIdleTask) {
+TEST_F(SchedulerHelperTest, TestPostIdleTask_EndIdlePeriod) {
+  int run_count = 0;
+  base::TimeTicks deadline_in_task;
+
+  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(100));
+  idle_task_runner_->PostIdleTask(
+      FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
+
+  RunUntilIdle();
+  EXPECT_EQ(0, run_count);
+
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
+  scheduler_helper_->EndIdlePeriod();
+  RunUntilIdle();
+  EXPECT_EQ(0, run_count);
+}
+
+TEST_F(SchedulerHelperTest, TestRepostingIdleTask) {
   int run_count = 0;
 
+  max_idle_task_reposts = 2;
   idle_task_runner_->PostIdleTask(
       FROM_HERE,
       base::Bind(&RepostingIdleTestTask, idle_task_runner_, &run_count));
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   EXPECT_EQ(1, run_count);
 
   // Reposted tasks shouldn't run until next idle period.
   RunUntilIdle();
   EXPECT_EQ(1, run_count);
 
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   EXPECT_EQ(2, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestIdleTaskExceedsDeadline) {

[rmcilroy, 2015/03/27 19:01:59]

Please move this test here (SchedulerHelperUnittest).

[alex clarke (OOO till 29th), 2015/03/30 12:23:30]

Done.

-  mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
-  int run_count = 0;
-
-  // Post two UpdateClockToDeadlineIdleTestTask tasks.
-  idle_task_runner_->PostIdleTask(
-      FROM_HERE, base::Bind(&UpdateClockToDeadlineIdleTestTask, clock_,
-                            default_task_runner_, &run_count));
-  idle_task_runner_->PostIdleTask(
-      FROM_HERE, base::Bind(&UpdateClockToDeadlineIdleTestTask, clock_,
-                            default_task_runner_, &run_count));
-
-  EnableIdleTasks();
-  RunUntilIdle();
-  // Only the first idle task should execute since it's used up the deadline.
-  EXPECT_EQ(1, run_count);
-
-  EnableIdleTasks();
-  RunUntilIdle();
-  // Second task should be run on the next idle period.
-  EXPECT_EQ(2, run_count);
-}
-
-TEST_F(RendererSchedulerImplTest, TestPostIdleTaskAfterWakeup) {
+TEST_F(SchedulerHelperTest, TestPostIdleTaskAfterWakeup) {
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
   idle_task_runner_->PostIdleTaskAfterWakeup(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
 
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Shouldn't run yet as no other task woke up the scheduler.
   EXPECT_EQ(0, run_count);
 
   idle_task_runner_->PostIdleTaskAfterWakeup(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
 
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Another after wakeup idle task shouldn't wake the scheduler.
   EXPECT_EQ(0, run_count);
 
   default_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
 
   RunUntilIdle();
-  EnableIdleTasks();  // Must start a new idle period before idle task runs.
+  // Must start a new idle period before idle task runs.
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Execution of default task queue task should trigger execution of idle task.
   EXPECT_EQ(2, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestPostIdleTaskAfterWakeupWhileAwake) {
+TEST_F(SchedulerHelperTest, TestPostIdleTaskAfterWakeupWhileAwake) {
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
   idle_task_runner_->PostIdleTaskAfterWakeup(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
   default_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
 
   RunUntilIdle();
-  EnableIdleTasks();  // Must start a new idle period before idle task runs.
+  // Must start a new idle period before idle task runs.
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Should run as the scheduler was already awakened by the normal task.
   EXPECT_EQ(1, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestPostIdleTaskWakesAfterWakeupIdleTask) {
+TEST_F(SchedulerHelperTest, TestPostIdleTaskWakesAfterWakeupIdleTask) {
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
   idle_task_runner_->PostIdleTaskAfterWakeup(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
   idle_task_runner_->PostIdleTask(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
 
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Must start a new idle period before after-wakeup idle task runs.
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Normal idle task should wake up after-wakeup idle task.
   EXPECT_EQ(2, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestDelayedEndIdlePeriodCanceled) {
-  int run_count = 0;

[rmcilroy, 2015/03/27 19:01:59]

Could you add a test similar to this one (using start/end idle period instead of
the frame stuff) - it's important that we test this delayed endidleperiod tasks
get canceled when we end an idle period early.

[alex clarke (OOO till 29th), 2015/03/30 12:23:30]

Done.  This was a bit of a pain, sadly there are only indirect methods of
testing that the closures got cancelled.

-
-  base::TimeTicks deadline_in_task;
-  idle_task_runner_->PostIdleTask(
-      FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
-
-  // Trigger the beginning of an idle period for 1000ms.
-  scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
-  DoMainFrame();
-
-  // End the idle period early (after 500ms), and send a WillBeginFrame which
-  // specifies that the next idle period should end 1000ms from now.
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(500));
-  scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
-
-  RunUntilIdle();
-  EXPECT_EQ(0, run_count);  // Not currently in an idle period.
-
-  // Trigger the start of the idle period before the task to end the previous
-  // idle period has been triggered.
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(400));
-  scheduler_->DidCommitFrameToCompositor();
-
-  // Post a task which simulates running until after the previous end idle
-  // period delayed task was scheduled for
-  scheduler_->DefaultTaskRunner()->PostTask(FROM_HERE, base::Bind(NullTask));
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(300));
-
-  RunUntilIdle();
-  EXPECT_EQ(1, run_count);  // We should still be in the new idle period.
-}
-
-TEST_F(RendererSchedulerImplTest, TestDefaultPolicy) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
-
-  EnableIdleTasks();
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("L1"), std::string("D1"),
-                                   std::string("C1"), std::string("D2"),
-                                   std::string("C2"), std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest, TestCompositorPolicy) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  EnableIdleTasks();
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2"),
-                                   std::string("L1"), std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest, TestCompositorPolicy_DidAnimateForInput) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
-
-  scheduler_->DidAnimateForInputOnCompositorThread();
-  EnableIdleTasks();
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2"),
-                                   std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest, TestTouchstartPolicy) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "L1 D1 C1 D2 C2");
-
-  // Observation of touchstart should defer execution of loading tasks.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2")));
-
-  // Meta events like TapDown/FlingCancel shouldn't affect the priority.
-  run_order.clear();
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingCancel));
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureTapDown));
-  RunUntilIdle();
-  EXPECT_TRUE(run_order.empty());
-
-  // Action events like ScrollBegin will kick us back into compositor priority,
-  // allowing servie of the loading and idle queues.
-  run_order.clear();
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureScrollBegin));
-  RunUntilIdle();
-  EXPECT_THAT(run_order, testing::ElementsAre(std::string("L1")));
-}
-
-TEST_F(RendererSchedulerImplTest,
-       DidReceiveInputEventOnCompositorThread_IgnoresMouseMove_WhenMouseUp) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::MouseMove));
-  EnableIdleTasks();
-  RunUntilIdle();
-  // Note compositor tasks are not prioritized.
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("D1"), std::string("C1"),
-                                   std::string("D2"), std::string("C2"),
-                                   std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest,
-       DidReceiveInputEventOnCompositorThread_MouseMove_WhenMouseDown) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(FakeInputEvent(
-      blink::WebInputEvent::MouseMove, blink::WebInputEvent::LeftButtonDown));
-  EnableIdleTasks();
-  RunUntilIdle();
-  // Note compositor tasks are prioritized.
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2"),
-                                   std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest,
-       DidReceiveInputEventOnCompositorThread_MouseWheel) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::MouseWheel));
-  EnableIdleTasks();
-  RunUntilIdle();
-  // Note compositor tasks are prioritized.
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2"),
-                                   std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest,
-       DidReceiveInputEventOnCompositorThread_IgnoresKeyboardEvents) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::KeyDown));
-  EnableIdleTasks();
-  RunUntilIdle();
-  // Note compositor tasks are not prioritized.
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("D1"), std::string("C1"),
-                                   std::string("D2"), std::string("C2"),
-                                   std::string("I1")));
-}
-
-TEST_F(RendererSchedulerImplTest,
-       TestCompositorPolicyDoesNotStarveDefaultTasks) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "D1 C1");
-
-  for (int i = 0; i < 20; i++) {
-    compositor_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
-  }
-  PostTestTasks(&run_order, "C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  RunUntilIdle();
-  // Ensure that the default D1 task gets to run at some point before the final
-  // C2 compositor task.
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("D1"),
-                                   std::string("C2")));
-}
-
-TEST_F(RendererSchedulerImplTest, TestCompositorPolicyEnds) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  DoMainFrame();
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2")));
-
-  run_order.clear();
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(1000));
-  PostTestTasks(&run_order, "D1 C1 D2 C2");
-
-  // Compositor policy mode should have ended now that the clock has advanced.
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("D1"), std::string("C1"),
-                                   std::string("D2"), std::string("C2")));
-}
-
-TEST_F(RendererSchedulerImplTest, TestTouchstartPolicyEndsAfterTimeout) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "L1 D1 C1 D2 C2");
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2")));
-
-  run_order.clear();
-  clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(1000));
-
-  // Don't post any compositor tasks to simulate a very long running event
-  // handler.
-  PostTestTasks(&run_order, "D1 D2");
-
-  // Touchstart policy mode should have ended now that the clock has advanced.
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("L1"), std::string("D1"),
-                                   std::string("D2")));
-}
-
-TEST_F(RendererSchedulerImplTest,
-       TestTouchstartPolicyEndsAfterConsecutiveTouchmoves) {
-  std::vector<std::string> run_order;
-  PostTestTasks(&run_order, "L1 D1 C1 D2 C2");
-
-  // Observation of touchstart should defer execution of idle and loading tasks.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  DoMainFrame();
-  RunUntilIdle();
-  EXPECT_THAT(run_order,
-              testing::ElementsAre(std::string("C1"), std::string("C2"),
-                                   std::string("D1"), std::string("D2")));
-
-  // Receiving the first touchmove will not affect scheduler priority.
-  run_order.clear();
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchMove));
-  DoMainFrame();
-  RunUntilIdle();
-  EXPECT_TRUE(run_order.empty());
-
-  // Receiving the second touchmove will kick us back into compositor priority.
-  run_order.clear();
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchMove));
-  RunUntilIdle();
-  EXPECT_THAT(run_order, testing::ElementsAre(std::string("L1")));
-}
-
-TEST_F(RendererSchedulerImplTest, TestIsHighPriorityWorkAnticipated) {
-  bool is_anticipated_before = false;
-  bool is_anticipated_after = false;
-
-  bool simulate_input = false;
-  default_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&AnticipationTestTask, scheduler_.get(), simulate_input,
-                 &is_anticipated_before, &is_anticipated_after));
-  RunUntilIdle();
-  // In its default state, without input receipt, the scheduler should indicate
-  // that no high-priority is anticipated.
-  EXPECT_FALSE(is_anticipated_before);
-  EXPECT_FALSE(is_anticipated_after);
-
-  simulate_input = true;
-  default_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&AnticipationTestTask, scheduler_.get(), simulate_input,
-                 &is_anticipated_before, &is_anticipated_after));
-  RunUntilIdle();
-  // When input is received, the scheduler should indicate that high-priority
-  // work is anticipated.
-  EXPECT_FALSE(is_anticipated_before);
-  EXPECT_TRUE(is_anticipated_after);
-
-  clock_->AdvanceNow(priority_escalation_after_input_duration() * 2);
-  simulate_input = false;
-  default_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&AnticipationTestTask, scheduler_.get(), simulate_input,
-                 &is_anticipated_before, &is_anticipated_after));
-  RunUntilIdle();
-  // Without additional input, the scheduler should indicate that high-priority
-  // work is no longer anticipated.
-  EXPECT_FALSE(is_anticipated_before);
-  EXPECT_FALSE(is_anticipated_after);
-}
-
-TEST_F(RendererSchedulerImplTest, TestShouldYield) {
-  bool should_yield_before = false;
-  bool should_yield_after = false;
-
-  default_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&PostingYieldingTestTask, scheduler_.get(),
-                            default_task_runner_, false, &should_yield_before,
-                            &should_yield_after));
-  RunUntilIdle();
-  // Posting to default runner shouldn't cause yielding.
-  EXPECT_FALSE(should_yield_before);
-  EXPECT_FALSE(should_yield_after);
-
-  default_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&PostingYieldingTestTask, scheduler_.get(),
-                            compositor_task_runner_, false,
-                            &should_yield_before, &should_yield_after));
-  RunUntilIdle();
-  // Posting while not in compositor priority shouldn't cause yielding.
-  EXPECT_FALSE(should_yield_before);
-  EXPECT_FALSE(should_yield_after);
-
-  default_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&PostingYieldingTestTask, scheduler_.get(),
-                            compositor_task_runner_, true, &should_yield_before,
-                            &should_yield_after));
-  RunUntilIdle();
-  // We should be able to switch to compositor priority mid-task.
-  EXPECT_FALSE(should_yield_before);
-  EXPECT_TRUE(should_yield_after);
-
-  // Receiving a touchstart should immediately trigger yielding, even if
-  // there's no immediately pending work in the compositor queue.
-  EXPECT_FALSE(scheduler_->ShouldYieldForHighPriorityWork());
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  EXPECT_TRUE(scheduler_->ShouldYieldForHighPriorityWork());
-  RunUntilIdle();
-}
-
-TEST_F(RendererSchedulerImplTest, SlowInputEvent) {
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-
-  // An input event should bump us into input priority.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // Simulate the input event being queued for a very long time. The compositor
-  // task we post here represents the enqueued input task.
-  clock_->AdvanceNow(priority_escalation_after_input_duration() * 2);
-  compositor_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
-  RunUntilIdle();
-
-  // Even though we exceeded the input priority escalation period, we should
-  // still be in compositor priority since the input remains queued.
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // Simulate the input event triggering a composition. This should start the
-  // countdown for going back into normal policy.
-  DoMainFrame();
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // After the escalation period ends we should go back into normal mode.
-  clock_->AdvanceNow(priority_escalation_after_input_duration() * 2);
-  RunUntilIdle();
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-}
-
-TEST_F(RendererSchedulerImplTest, SlowNoOpInputEvent) {
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-
-  // An input event should bump us into input priority.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // Simulate the input event being queued for a very long time. The compositor
-  // task we post here represents the enqueued input task.
-  clock_->AdvanceNow(priority_escalation_after_input_duration() * 2);
-  compositor_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
-  RunUntilIdle();
-
-  // Even though we exceeded the input priority escalation period, we should
-  // still be in compositor priority since the input remains queued.
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // If we let the compositor queue drain, we should fall out of input
-  // priority.
-  clock_->AdvanceNow(priority_escalation_after_input_duration() * 2);
-  RunUntilIdle();
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-}
-
-TEST_F(RendererSchedulerImplTest, NoOpInputEvent) {
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-
-  // An input event should bump us into input priority.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // If nothing else happens after this, we should drop out of compositor
-  // priority after the escalation period ends and stop polling.
-  clock_->AdvanceNow(priority_escalation_after_input_duration() * 2);
-  RunUntilIdle();
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-  EXPECT_FALSE(mock_task_runner_->HasPendingTasks());
-}
-
-TEST_F(RendererSchedulerImplTest, NoOpInputEventExtendsEscalationPeriod) {
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-
-  // Simulate one handled input event.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureScrollBegin));
-  RunUntilIdle();
-  DoMainFrame();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // Send a no-op input event in the middle of the escalation period.
-  clock_->AdvanceNow(priority_escalation_after_input_duration() / 2);
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureScrollUpdate));
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // The escalation period should have been extended by the new input event.
-  clock_->AdvanceNow(3 * priority_escalation_after_input_duration() / 4);
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  clock_->AdvanceNow(priority_escalation_after_input_duration() / 2);
-  RunUntilIdle();
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-}
-
-TEST_F(RendererSchedulerImplTest, InputArrivesAfterBeginFrame) {
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-
-  cc::BeginFrameArgs args = cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL);
-  clock_->AdvanceNow(priority_escalation_after_input_duration() / 2);
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::GestureScrollBegin));
-
-  // Simulate a BeginMainFrame task from the past.
-  clock_->AdvanceNow(2 * priority_escalation_after_input_duration());
-  scheduler_->WillBeginFrame(args);
-  scheduler_->DidCommitFrameToCompositor();
-
-  // This task represents the queued-up input event.
-  compositor_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
-
-  // Should remain in input priority policy since the input event hasn't been
-  // processed yet.
-  clock_->AdvanceNow(2 * priority_escalation_after_input_duration());
-  RunUntilIdle();
-  EXPECT_EQ(Policy::COMPOSITOR_PRIORITY, CurrentPolicy());
-
-  // Process the input event with a new BeginMainFrame.
-  DoMainFrame();
-  clock_->AdvanceNow(2 * priority_escalation_after_input_duration());
-  RunUntilIdle();
-  EXPECT_EQ(Policy::NORMAL, CurrentPolicy());
-}
-
-class RendererSchedulerImplForTest : public RendererSchedulerImpl {
+class SchedulerHelperWithMessageLoopTest : public SchedulerHelperTest {
  public:
-  RendererSchedulerImplForTest(
-      scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner)
-      : RendererSchedulerImpl(main_task_runner), update_policy_count_(0) {}
-
-  void UpdatePolicyLocked() override {
-    update_policy_count_++;
-    RendererSchedulerImpl::UpdatePolicyLocked();
-  }
-
-  int update_policy_count_;
-};
-
-TEST_F(RendererSchedulerImplTest, OnlyOnePendingUrgentPolicyUpdatey) {
-  RendererSchedulerImplForTest* mock_scheduler =
-      new RendererSchedulerImplForTest(nestable_task_runner_);
-  scheduler_.reset(mock_scheduler);
-
-  EnsureUrgentPolicyUpdatePostedOnMainThread();
-  EnsureUrgentPolicyUpdatePostedOnMainThread();
-  EnsureUrgentPolicyUpdatePostedOnMainThread();
-  EnsureUrgentPolicyUpdatePostedOnMainThread();
-
-  RunUntilIdle();
-
-  EXPECT_EQ(1, mock_scheduler->update_policy_count_);
-}
-
-TEST_F(RendererSchedulerImplTest, OnePendingDelayedAndOneUrgentUpdatePolicy) {
-  RendererSchedulerImplForTest* mock_scheduler =
-      new RendererSchedulerImplForTest(nestable_task_runner_);
-  scheduler_.reset(mock_scheduler);
-  scheduler_->SetTimeSourceForTesting(clock_);
-  mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
-
-  ScheduleDelayedPolicyUpdate(base::TimeDelta::FromMilliseconds(1));
-  EnsureUrgentPolicyUpdatePostedOnMainThread();
-
-  RunUntilIdle();
-
-  // We expect both the urgent and the delayed updates to run.
-  EXPECT_EQ(2, mock_scheduler->update_policy_count_);
-}
-
-TEST_F(RendererSchedulerImplTest, OneUrgentAndOnePendingDelayedUpdatePolicy) {
-  RendererSchedulerImplForTest* mock_scheduler =
-      new RendererSchedulerImplForTest(nestable_task_runner_);
-  scheduler_.reset(mock_scheduler);
-  scheduler_->SetTimeSourceForTesting(clock_);
-  mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
-
-  EnsureUrgentPolicyUpdatePostedOnMainThread();
-  ScheduleDelayedPolicyUpdate(base::TimeDelta::FromMilliseconds(1));
-
-  RunUntilIdle();
-
-  // We expect both the urgent and the delayed updates to run.
-  EXPECT_EQ(2, mock_scheduler->update_policy_count_);
-}
-
-TEST_F(RendererSchedulerImplTest, UpdatePolicyCountTriggeredByOneInputEvent) {
-  RendererSchedulerImplForTest* mock_scheduler =
-      new RendererSchedulerImplForTest(nestable_task_runner_);
-  scheduler_.reset(mock_scheduler);
-  scheduler_->SetTimeSourceForTesting(clock_);
-  mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-
-  RunUntilIdle();
-
-  // We expect an urgent policy update followed by a delayed one 100ms later.
-  EXPECT_EQ(2, mock_scheduler->update_policy_count_);
-}
-
-TEST_F(RendererSchedulerImplTest, UpdatePolicyCountTriggeredByTwoInputEvents) {
-  RendererSchedulerImplForTest* mock_scheduler =
-      new RendererSchedulerImplForTest(nestable_task_runner_);
-  scheduler_.reset(mock_scheduler);
-  scheduler_->SetTimeSourceForTesting(clock_);
-  mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchMove));
-
-  RunUntilIdle();
-
-  // We expect an urgent policy update followed by a delayed one 100ms later.
-  EXPECT_EQ(2, mock_scheduler->update_policy_count_);
-}
-
-TEST_F(RendererSchedulerImplTest, EnsureUpdatePolicyNotTriggeredTooOften) {
-  RendererSchedulerImplForTest* mock_scheduler =
-      new RendererSchedulerImplForTest(nestable_task_runner_);
-  scheduler_.reset(mock_scheduler);
-  scheduler_->SetTimeSourceForTesting(clock_);
-  mock_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
-
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchMove));
-
-  // We expect the first call to IsHighPriorityWorkAnticipated to be called
-  // after recieving an input event (but before the UpdateTask was processed) to
-  // call UpdatePolicy.
-  EXPECT_EQ(0, mock_scheduler->update_policy_count_);
-  scheduler_->IsHighPriorityWorkAnticipated();
-  EXPECT_EQ(1, mock_scheduler->update_policy_count_);
-  // Subsequent calls should not call UpdatePolicy.
-  scheduler_->IsHighPriorityWorkAnticipated();
-  scheduler_->IsHighPriorityWorkAnticipated();
-  scheduler_->IsHighPriorityWorkAnticipated();
-  scheduler_->ShouldYieldForHighPriorityWork();
-  scheduler_->ShouldYieldForHighPriorityWork();
-  scheduler_->ShouldYieldForHighPriorityWork();
-  scheduler_->ShouldYieldForHighPriorityWork();
-
-  EXPECT_EQ(1, mock_scheduler->update_policy_count_);
-
-  RunUntilIdle();
-  // We expect both the urgent and the delayed updates to run in addition to the
-  // earlier updated cause by IsHighPriorityWorkAnticipated.
-  EXPECT_EQ(3, mock_scheduler->update_policy_count_);
-}
-
-class RendererSchedulerImplWithMessageLoopTest
-    : public RendererSchedulerImplTest {
- public:
-  RendererSchedulerImplWithMessageLoopTest()
-      : RendererSchedulerImplTest(new base::MessageLoop()) {}
-  ~RendererSchedulerImplWithMessageLoopTest() override {}
+  SchedulerHelperWithMessageLoopTest()
+      : SchedulerHelperTest(new base::MessageLoop()) {}
+  ~SchedulerHelperWithMessageLoopTest() override {}
 
   void PostFromNestedRunloop(std::vector<
       std::pair<SingleThreadIdleTaskRunner::IdleTask, bool>>* tasks) {
     base::MessageLoop::ScopedNestableTaskAllower allow(message_loop_.get());
     for (std::pair<SingleThreadIdleTaskRunner::IdleTask, bool>& pair : *tasks) {
       if (pair.second) {
         idle_task_runner_->PostIdleTask(FROM_HERE, pair.first);
       } else {
         idle_task_runner_->PostNonNestableIdleTask(FROM_HERE, pair.first);
       }
     }
-    EnableIdleTasks();
+    scheduler_helper_->StartIdlePeriod(
+        SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
     message_loop_->RunUntilIdle();
   }
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(RendererSchedulerImplWithMessageLoopTest);
+  DISALLOW_COPY_AND_ASSIGN(SchedulerHelperWithMessageLoopTest);
 };
 
-TEST_F(RendererSchedulerImplWithMessageLoopTest,
+TEST_F(SchedulerHelperWithMessageLoopTest,
        NonNestableIdleTaskDoesntExecuteInNestedLoop) {
   std::vector<std::string> order;
   idle_task_runner_->PostIdleTask(
       FROM_HERE,
       base::Bind(&AppendToVectorIdleTestTask, &order, std::string("1")));
   idle_task_runner_->PostIdleTask(
       FROM_HERE,
       base::Bind(&AppendToVectorIdleTestTask, &order, std::string("2")));
 
   std::vector<std::pair<SingleThreadIdleTaskRunner::IdleTask, bool>>
       tasks_to_post_from_nested_loop;
   tasks_to_post_from_nested_loop.push_back(std::make_pair(
       base::Bind(&AppendToVectorIdleTestTask, &order, std::string("3")),
       false));
   tasks_to_post_from_nested_loop.push_back(std::make_pair(
       base::Bind(&AppendToVectorIdleTestTask, &order, std::string("4")), true));
   tasks_to_post_from_nested_loop.push_back(std::make_pair(
       base::Bind(&AppendToVectorIdleTestTask, &order, std::string("5")), true));
 
   default_task_runner_->PostTask(
       FROM_HERE,
-      base::Bind(
-          &RendererSchedulerImplWithMessageLoopTest::PostFromNestedRunloop,
-          base::Unretained(this),
-          base::Unretained(&tasks_to_post_from_nested_loop)));
+      base::Bind(&SchedulerHelperWithMessageLoopTest::PostFromNestedRunloop,
+                 base::Unretained(this),
+                 base::Unretained(&tasks_to_post_from_nested_loop)));
 
-  EnableIdleTasks();
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   // Note we expect task 3 to run last because it's non-nestable.
   EXPECT_THAT(order, testing::ElementsAre(std::string("1"), std::string("2"),
                                           std::string("4"), std::string("5"),
                                           std::string("3")));
 }
 
-TEST_F(RendererSchedulerImplTest, TestLongIdlePeriod) {
+TEST_F(SchedulerHelperTest, TestLongIdlePeriod) {
   base::TimeTicks expected_deadline =
       clock_->Now() + maximum_idle_period_duration();
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
   idle_task_runner_->PostIdleTask(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
 
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .Times(2)
+      .WillRepeatedly(Return(true));
+
   RunUntilIdle();
   EXPECT_EQ(0, run_count);  // Shouldn't run yet as no idle period.
 
-  scheduler_->BeginFrameNotExpectedSoon();
+  scheduler_helper_->InitiateLongIdlePeriod();
   RunUntilIdle();
   EXPECT_EQ(1, run_count);  // Should have run in a long idle time.
   EXPECT_EQ(expected_deadline, deadline_in_task);
 }
 
-TEST_F(RendererSchedulerImplTest, TestLongIdlePeriodWithPendingDelayedTask) {
+TEST_F(SchedulerHelperTest, TestLongIdlePeriodWithPendingDelayedTask) {
   base::TimeDelta pending_task_delay = base::TimeDelta::FromMilliseconds(30);
   base::TimeTicks expected_deadline = clock_->Now() + pending_task_delay;
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .Times(2)
+      .WillRepeatedly(Return(true));
+
   idle_task_runner_->PostIdleTask(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
-  default_task_runner_->PostDelayedTask(
-      FROM_HERE, base::Bind(&NullTask), pending_task_delay);
+  default_task_runner_->PostDelayedTask(FROM_HERE, base::Bind(&NullTask),
+                                        pending_task_delay);
 
-  scheduler_->BeginFrameNotExpectedSoon();
+  scheduler_helper_->InitiateLongIdlePeriod();
   RunUntilIdle();
   EXPECT_EQ(1, run_count);  // Should have run in a long idle time.
   EXPECT_EQ(expected_deadline, deadline_in_task);
 }
 
-TEST_F(RendererSchedulerImplTest,
-       TestLongIdlePeriodWithLatePendingDelayedTask) {
+TEST_F(SchedulerHelperTest, TestLongIdlePeriodWithLatePendingDelayedTask) {
   base::TimeDelta pending_task_delay = base::TimeDelta::FromMilliseconds(10);
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
-  default_task_runner_->PostDelayedTask(
-      FROM_HERE, base::Bind(&NullTask), pending_task_delay);
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .Times(3)
+      .WillRepeatedly(Return(true));
+
+  default_task_runner_->PostDelayedTask(FROM_HERE, base::Bind(&NullTask),
+                                        pending_task_delay);
 
   // Advance clock until after delayed task was meant to be run.
   clock_->AdvanceNow(base::TimeDelta::FromMilliseconds(20));
 
-  // Post an idle task and BeginFrameNotExpectedSoon to initiate a long idle
-  // period. Since there is a late pending delayed task this shouldn't actually
-  // start an idle period.
+  // Post an idle task and then InitiateLongIdlePeriod. Since there is a late
+  // pending delayed task this shouldn't actually start an idle period.
   idle_task_runner_->PostIdleTask(
       FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
-  scheduler_->BeginFrameNotExpectedSoon();
+  scheduler_helper_->InitiateLongIdlePeriod();
   RunUntilIdle();
   EXPECT_EQ(0, run_count);
 
   // After the delayed task has been run we should trigger an idle period.
   clock_->AdvanceNow(maximum_idle_period_duration());
   RunUntilIdle();
   EXPECT_EQ(1, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestLongIdlePeriodRepeating) {
+TEST_F(SchedulerHelperTest, TestLongIdlePeriodRepeating) {
   int run_count = 0;
 
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .Times(4)
+      .WillRepeatedly(Return(true));
+
+  max_idle_task_reposts = 3;
   idle_task_runner_->PostIdleTask(
       FROM_HERE,
       base::Bind(&RepostingIdleTestTask, idle_task_runner_, &run_count));
 
-  scheduler_->BeginFrameNotExpectedSoon();
+  scheduler_helper_->InitiateLongIdlePeriod();
   RunUntilIdle();
   EXPECT_EQ(1, run_count);  // Should only run once per idle period.
 
   // Advance time to start of next long idle period and check task reposted task
   // gets run.
   clock_->AdvanceNow(maximum_idle_period_duration());
   RunUntilIdle();
   EXPECT_EQ(2, run_count);
 
-  // Advance time to start of next long idle period then end idle period with a
-  // new BeginMainFrame and check idle task doesn't run.
+  // Advance time to start of next long idle period and check task reposted task
+  // gets run.
   clock_->AdvanceNow(maximum_idle_period_duration());

[rmcilroy, 2015/03/27 19:01:59]

Please make this do the same as the previous test did (end idle period and check
that the Task isn't run).

[alex clarke (OOO till 29th), 2015/03/30 12:23:30]

Done.

-  scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
   RunUntilIdle();
-  EXPECT_EQ(2, run_count);
+  EXPECT_EQ(3, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestLongIdlePeriodDoesNotWakeScheduler) {
+TEST_F(SchedulerHelperTest, TestLongIdlePeriodDoesNotWakeScheduler) {
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .Times(3)
+      .WillRepeatedly(Return(true));
+
   // Start a long idle period and get the time it should end.
-  scheduler_->BeginFrameNotExpectedSoon();
+  scheduler_helper_->InitiateLongIdlePeriod();
   // The scheduler should not run the initiate_next_long_idle_period task if
   // there are no idle tasks and no other task woke up the scheduler, thus
   // the idle period deadline shouldn't update at the end of the current long
   // idle period.
-  base::TimeTicks idle_period_deadline = CurrentIdleTaskDeadline();
+  base::TimeTicks idle_period_deadline = CurrentIdleTaskDeadlineForTesting();
   clock_->AdvanceNow(maximum_idle_period_duration());
   RunUntilIdle();
 
-  base::TimeTicks new_idle_period_deadline = CurrentIdleTaskDeadline();
+  base::TimeTicks new_idle_period_deadline =
+      CurrentIdleTaskDeadlineForTesting();
   EXPECT_EQ(idle_period_deadline, new_idle_period_deadline);
 
   // Posting a after-wakeup idle task also shouldn't wake the scheduler or
   // initiate the next long idle period.
   idle_task_runner_->PostIdleTaskAfterWakeup(
-      FROM_HERE,
-      base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
+      FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
   RunUntilIdle();
-  new_idle_period_deadline = CurrentIdleTaskDeadline();
+  new_idle_period_deadline = CurrentIdleTaskDeadlineForTesting();
   EXPECT_EQ(idle_period_deadline, new_idle_period_deadline);
   EXPECT_EQ(0, run_count);
 
   // Running a normal task should initiate a new long idle period though.
   default_task_runner_->PostTask(FROM_HERE, base::Bind(&NullTask));
   RunUntilIdle();
-  new_idle_period_deadline = CurrentIdleTaskDeadline();
+  new_idle_period_deadline = CurrentIdleTaskDeadlineForTesting();
   EXPECT_EQ(idle_period_deadline + maximum_idle_period_duration(),
             new_idle_period_deadline);
 
   EXPECT_EQ(1, run_count);
 }
 
-TEST_F(RendererSchedulerImplTest, TestLongIdlePeriodInTouchStartPolicy) {
+TEST_F(SchedulerHelperTest, TestLongIdlePeriodCantEnterLongIdlePeriod) {

[rmcilroy, 2015/03/27 19:01:59]

nit - TestLongIdlePeriodWhenNotCanEnterLongIdlePeriod

[alex clarke (OOO till 29th), 2015/03/30 12:23:30]

Done.

+  base::TimeDelta delay = base::TimeDelta::FromMilliseconds(1000);
+  base::TimeDelta halfDelay = base::TimeDelta::FromMilliseconds(500);
+  base::TimeTicks delayOver = clock_->Now() + delay;
   base::TimeTicks deadline_in_task;
   int run_count = 0;
 
+  ON_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .WillByDefault(Invoke([&delay, &delayOver](
+          base::TimeTicks now,
+          base::TimeDelta* next_long_idle_period_delay_out) {
+        if (now >= delayOver)
+          return true;
+        *next_long_idle_period_delay_out = delay;
+        return false;
+      }));
+
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _)).Times(3);
+
   idle_task_runner_->PostIdleTask(
-      FROM_HERE,
-      base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
+      FROM_HERE, base::Bind(&IdleTestTask, &run_count, &deadline_in_task));
 
-  // Observation of touchstart should defer the start of the long idle period.
-  scheduler_->DidReceiveInputEventOnCompositorThread(
-      FakeInputEvent(blink::WebInputEvent::TouchStart));
-  scheduler_->BeginFrameNotExpectedSoon();
+  // Make sure Idle tasks don't run until the delay has occured.
+  scheduler_helper_->InitiateLongIdlePeriod();
   RunUntilIdle();
   EXPECT_EQ(0, run_count);
 
-  // The long idle period should start after the touchstart policy has finished.
-  clock_->AdvanceNow(priority_escalation_after_input_duration());
+  clock_->AdvanceNow(halfDelay);
+  RunUntilIdle();
+  EXPECT_EQ(0, run_count);
+
+  // Delay is finished, idle task should run.
+  clock_->AdvanceNow(halfDelay);
   RunUntilIdle();
   EXPECT_EQ(1, run_count);
 }
 
-void TestCanExceedIdleDeadlineIfRequiredTask(RendererScheduler* scheduler,
+void TestCanExceedIdleDeadlineIfRequiredTask(SchedulerHelperForTest* scheduler,
                                              bool* can_exceed_idle_deadline_out,
                                              int* run_count,
                                              base::TimeTicks deadline) {
   *can_exceed_idle_deadline_out = scheduler->CanExceedIdleDeadlineIfRequired();
   (*run_count)++;
 }
 
-TEST_F(RendererSchedulerImplTest, CanExceedIdleDeadlineIfRequired) {
+TEST_F(SchedulerHelperTest, CanExceedIdleDeadlineIfRequired) {
   int run_count = 0;
   bool can_exceed_idle_deadline = false;
 
+  EXPECT_CALL(*scheduler_helper_, CanEnterLongIdlePeriod(_, _))
+      .Times(3)
+      .WillRepeatedly(Return(true));
+
   // Should return false if not in an idle period.
-  EXPECT_FALSE(scheduler_->CanExceedIdleDeadlineIfRequired());
+  EXPECT_FALSE(scheduler_helper_->CanExceedIdleDeadlineIfRequired());
 
   // Should return false for short idle periods.
   idle_task_runner_->PostIdleTask(
-      FROM_HERE,
-      base::Bind(&TestCanExceedIdleDeadlineIfRequiredTask, scheduler_.get(),
-                 &can_exceed_idle_deadline, &run_count));
-  EnableIdleTasks();
+      FROM_HERE, base::Bind(&TestCanExceedIdleDeadlineIfRequiredTask,
+                            scheduler_helper_.get(), &can_exceed_idle_deadline,
+                            &run_count));
+  scheduler_helper_->StartIdlePeriod(
+      SchedulerHelperForTest::IdlePeriodState::IN_SHORT_IDLE_PERIOD);
   RunUntilIdle();
   EXPECT_EQ(1, run_count);
   EXPECT_FALSE(can_exceed_idle_deadline);
 
   // Should return false for a long idle period which is shortened due to a
   // pending delayed task.
   default_task_runner_->PostDelayedTask(FROM_HERE, base::Bind(&NullTask),
                                         base::TimeDelta::FromMilliseconds(10));
   idle_task_runner_->PostIdleTask(
-      FROM_HERE,
-      base::Bind(&TestCanExceedIdleDeadlineIfRequiredTask, scheduler_.get(),
-                 &can_exceed_idle_deadline, &run_count));
-  scheduler_->BeginFrameNotExpectedSoon();
+      FROM_HERE, base::Bind(&TestCanExceedIdleDeadlineIfRequiredTask,
+                            scheduler_helper_.get(), &can_exceed_idle_deadline,
+                            &run_count));
+  scheduler_helper_->InitiateLongIdlePeriod();
   RunUntilIdle();
   EXPECT_EQ(2, run_count);
   EXPECT_FALSE(can_exceed_idle_deadline);
 
   // Next long idle period will be for the maximum time, so
   // CanExceedIdleDeadlineIfRequired should return true.
   clock_->AdvanceNow(maximum_idle_period_duration());
   idle_task_runner_->PostIdleTask(
-      FROM_HERE,
-      base::Bind(&TestCanExceedIdleDeadlineIfRequiredTask, scheduler_.get(),
-                 &can_exceed_idle_deadline, &run_count));
+      FROM_HERE, base::Bind(&TestCanExceedIdleDeadlineIfRequiredTask,
+                            scheduler_helper_.get(), &can_exceed_idle_deadline,
+                            &run_count));
   RunUntilIdle();
   EXPECT_EQ(3, run_count);
   EXPECT_TRUE(can_exceed_idle_deadline);
+}
 
-  // Next long idle period will be for the maximum time, so
-  // CanExceedIdleDeadlineIfRequired should return true.
-  scheduler_->WillBeginFrame(cc::BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, clock_->Now(), base::TimeTicks(),
-      base::TimeDelta::FromMilliseconds(1000), cc::BeginFrameArgs::NORMAL));
-  EXPECT_FALSE(scheduler_->CanExceedIdleDeadlineIfRequired());
+TEST_F(SchedulerHelperTest, IsShutdown) {
+  EXPECT_FALSE(scheduler_helper_->IsShutdown());
+
+  scheduler_helper_->Shutdown();
+  EXPECT_TRUE(scheduler_helper_->IsShutdown());
 }
 
 }  // namespace content