scheduler: Tell v8 about the current RAIL mode

components/scheduler/renderer/renderer_scheduler_impl_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/renderer/renderer_scheduler_impl.h"
 
 #include <utility>
 
 #include "base/callback.h"
 #include "base/macros.h"
@@ skipping 172 matching lines @@
   using RendererSchedulerImpl::EstimateLongestJankFreeTaskDuration;
 
   RendererSchedulerImplForTest(
       scoped_refptr<SchedulerTqmDelegate> main_task_runner)
       : RendererSchedulerImpl(main_task_runner), update_policy_count_(0) {}
 
   void UpdatePolicyLocked(UpdateType update_type) override {
     update_policy_count_++;
     RendererSchedulerImpl::UpdatePolicyLocked(update_type);
 
-    std::string use_case =
-        RendererScheduler::UseCaseToString(MainThreadOnly().current_use_case);
+    std::string use_case = RendererSchedulerImpl::UseCaseToString(
+        MainThreadOnly().current_use_case);
     if (MainThreadOnly().touchstart_expected_soon) {
       use_cases_.push_back(use_case + " touchstart expected");
     } else {
       use_cases_.push_back(use_case);
     }
   }
 
   void EnsureUrgentPolicyUpdatePostedOnMainThread() {
     base::AutoLock lock(any_thread_lock_);
     RendererSchedulerImpl::EnsureUrgentPolicyUpdatePostedOnMainThread(
         FROM_HERE);
   }
 
   void ScheduleDelayedPolicyUpdate(base::TimeTicks now, base::TimeDelta delay) {
     delayed_update_policy_runner_.SetDeadline(FROM_HERE, delay, now);
   }
 
   bool BeginMainFrameOnCriticalPath() {
     base::AutoLock lock(any_thread_lock_);
     return AnyThread().begin_main_frame_on_critical_path;
   }
 
   int update_policy_count_;
   std::vector<std::string> use_cases_;
 };
 
 // Lets gtest print human readable Policy values.
 ::std::ostream& operator<<(::std::ostream& os,
-                           const RendererScheduler::UseCase& use_case) {
-  return os << RendererScheduler::UseCaseToString(use_case);
+                           const RendererSchedulerImpl::UseCase& use_case) {
+  return os << RendererSchedulerImpl::UseCaseToString(use_case);
 }
 
 class RendererSchedulerImplTest : public testing::Test {
  public:
   using UseCase = RendererSchedulerImpl::UseCase;
 
   RendererSchedulerImplTest() : clock_(new base::SimpleTestTickClock()) {
     clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
   }
 
@@ skipping 252 matching lines @@
 
   UseCase CurrentUseCase() {
     return scheduler_->MainThreadOnly().current_use_case;
   }
 
   UseCase ForceUpdatePolicyAndGetCurrentUseCase() {
     scheduler_->ForceUpdatePolicy();
     return scheduler_->MainThreadOnly().current_use_case;
   }
 
+  v8::RAILMode RAILMode() {
+    return scheduler_->MainThreadOnly().current_policy.rail_mode;
+  }
+
+  bool BeginFrameNotExpectedSoon() {
+    return scheduler_->MainThreadOnly().begin_frame_not_expected_soon;
+  }
+
   bool TouchStartExpectedSoon() {
     return scheduler_->MainThreadOnly().touchstart_expected_soon;
   }
 
   bool HaveSeenABeginMainframe() {
     return scheduler_->MainThreadOnly().have_seen_a_begin_main_frame;
   }
 
   bool LoadingTasksSeemExpensive() {
     return scheduler_->MainThreadOnly().loading_tasks_seem_expensive;
@@ skipping 333 matching lines @@
 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")));
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_CompositorHandlesInput_WithTouchHandler) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   EnableIdleTasks();
   SimulateCompositorGestureStart(TouchEventPolicy::SEND_TOUCH_START);
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("L1"), std::string("D1"),
                                    std::string("D2"), std::string("I1"),
                                    std::string("C1"), std::string("C2")));
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
+            CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_MainThreadHandlesInput_WithoutScrollUpdates) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   EnableIdleTasks();
   SimulateMainThreadGestureWithoutScrollUpdates();
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("C2"),
                                    std::string("L1"), std::string("D1"),
                                    std::string("D2"), std::string("I1")));
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_MainThreadHandlesInput_WithoutPreventDefault) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   EnableIdleTasks();
   SimulateMainThreadGestureWithoutPreventDefault();
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("L1"), std::string("D1"),
                                    std::string("D2"), std::string("I1"),
                                    std::string("C1"), std::string("C2")));
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
+            CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_CompositorHandlesInput_LongGestureDuration) {
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   EnableIdleTasks();
   SimulateCompositorGestureStart(TouchEventPolicy::SEND_TOUCH_START);
 
   base::TimeTicks loop_end_time =
       clock_->NowTicks() + base::TimeDelta::FromMilliseconds(
@@ skipping 11 matching lines @@
   }
 
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("C2"),
                                    std::string("L1"), std::string("D1"),
                                    std::string("D2")));
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
+            CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_CompositorHandlesInput_WithoutTouchHandler) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   EnableIdleTasks();
   SimulateCompositorGestureStart(TouchEventPolicy::DONT_SEND_TOUCH_START);
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("L1"), std::string("D1"),
                                    std::string("D2"), std::string("I1"),
                                    std::string("C1"), std::string("C2")));
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
+            CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_MainThreadHandlesInput_WithTouchHandler) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   EnableIdleTasks();
   SimulateMainThreadGestureStart(TouchEventPolicy::SEND_TOUCH_START,
                                  blink::WebInputEvent::GestureScrollBegin);
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("C2"),
                                    std::string("L1"), std::string("D1"),
                                    std::string("D2"), std::string("I1")));
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
   scheduler_->DidHandleInputEventOnMainThread(
       FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestCompositorPolicy_MainThreadHandlesInput_WithoutTouchHandler) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 I1 D1 C1 D2 C2");
 
   EnableIdleTasks();
   SimulateMainThreadGestureStart(TouchEventPolicy::DONT_SEND_TOUCH_START,
                                  blink::WebInputEvent::GestureScrollBegin);
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("C2"),
                                    std::string("L1"), std::string("D1"),
                                    std::string("D2"), std::string("I1")));
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
   scheduler_->DidHandleInputEventOnMainThread(
       FakeInputEvent(blink::WebInputEvent::GestureFlingStart));
 }
 
 TEST_F(RendererSchedulerImplTest, TestCompositorPolicy_DidAnimateForInput) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   scheduler_->DidAnimateForInputOnCompositorThread();
   // Note DidAnimateForInputOnCompositorThread does not by itself trigger a
   // policy update.
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
             ForceUpdatePolicyAndGetCurrentUseCase());
   EnableIdleTasks();
   RunUntilIdle();
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("D1"), std::string("D2"),
                                    std::string("I1"), std::string("C1"),
                                    std::string("C2")));
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
+            CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest, Navigation_ResetsTaskCostEstimations) {
   std::vector<std::string> run_order;
 
   SimulateExpensiveTasks(timer_task_runner_);
   scheduler_->OnNavigationStarted();
   PostTestTasks(&run_order, "C1 T1");
 
   SimulateMainThreadGestureStart(TouchEventPolicy::DONT_SEND_TOUCH_START,
@@ skipping 12 matching lines @@
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateExpensiveTasks(timer_task_runner_);
   DoMainFrame();
   SimulateMainThreadGestureStart(TouchEventPolicy::SEND_TOUCH_START,
                                  blink::WebInputEvent::GestureScrollUpdate);
 
   PostTestTasks(&run_order, "C1 T1");
 
   RunUntilIdle();
   EXPECT_FALSE(TouchStartExpectedSoon());
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_GESTURE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_GESTURE,
+            CurrentUseCase());
 
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("C1")));
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveTimersDoRunWhenMainThreadInputHandling) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateExpensiveTasks(timer_task_runner_);
   DoMainFrame();
   SimulateMainThreadGestureStart(TouchEventPolicy::SEND_TOUCH_START,
                                  blink::WebInputEvent::Undefined);
 
   PostTestTasks(&run_order, "C1 T1");
 
   RunUntilIdle();
   EXPECT_FALSE(TouchStartExpectedSoon());
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
 
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("T1")));
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveTimersDoRunWhenMainThreadScrolling_AndOnCriticalPath) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateExpensiveTasks(timer_task_runner_);
   DoMainFrameOnCriticalPath();
   SimulateMainThreadGestureStart(TouchEventPolicy::SEND_TOUCH_START,
                                  blink::WebInputEvent::GestureScrollBegin);
 
   PostTestTasks(&run_order, "C1 T1");
 
   RunUntilIdle();
   EXPECT_FALSE(TouchStartExpectedSoon());
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
 
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("T1")));
 }
 
 TEST_F(RendererSchedulerImplTest, TestTouchstartPolicy_Compositor) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "L1 D1 C1 D2 C2 T1 T2");
 
@@ skipping 89 matching lines @@
   scheduler_->OnNavigationStarted();
   EnableIdleTasks();
   RunUntilIdle();
 
   // In loading policy, loading tasks are prioritized other others.
   std::string loading_policy_expected[] = {
       std::string("D1"), std::string("L1"), std::string("D2"),
       std::string("L2"), std::string("C1"), std::string("T1"),
       std::string("C2"), std::string("T2"), std::string("I1")};
   EXPECT_THAT(run_order, testing::ElementsAreArray(loading_policy_expected));
-  EXPECT_EQ(RendererScheduler::UseCase::LOADING, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::LOADING, CurrentUseCase());
 
   // Advance 15s and try again, the loading policy should have ended and the
   // task order should return to the NONE use case where loading tasks are no
   // longer prioritized.
   clock_->Advance(base::TimeDelta::FromMilliseconds(150000));
   run_order.clear();
   PostTestTasks(&run_order, "I1 D1 C1 T1 L1 D2 C2 T2 L2");
   EnableIdleTasks();
   RunUntilIdle();
 
   std::string default_order_expected[] = {
       std::string("D1"), std::string("C1"), std::string("T1"),
       std::string("L1"), std::string("D2"), std::string("C2"),
       std::string("T2"), std::string("L2"), std::string("I1")};
   EXPECT_THAT(run_order, testing::ElementsAreArray(default_order_expected));
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        EventConsumedOnCompositorThread_IgnoresMouseMove_WhenMouseUp) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
 
   EnableIdleTasks();
   scheduler_->DidHandleInputEventOnCompositorThread(
       FakeInputEvent(blink::WebInputEvent::MouseMove),
       RendererScheduler::InputEventState::EVENT_CONSUMED_BY_COMPOSITOR);
   RunUntilIdle();
   // Note compositor tasks are not prioritized.
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("D1"), std::string("C1"),
                                    std::string("D2"), std::string("C2"),
                                    std::string("I1")));
 }
 
 TEST_F(RendererSchedulerImplTest,
        EventForwardedToMainThread_IgnoresMouseMove_WhenMouseUp) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
 
   EnableIdleTasks();
   scheduler_->DidHandleInputEventOnCompositorThread(
       FakeInputEvent(blink::WebInputEvent::MouseMove),
       RendererScheduler::InputEventState::EVENT_FORWARDED_TO_MAIN_THREAD);
   RunUntilIdle();
   // Note compositor tasks are not prioritized.
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("D1"), std::string("C1"),
                                    std::string("D2"), std::string("C2"),
                                    std::string("I1")));
 }
 
 TEST_F(RendererSchedulerImplTest,
        EventConsumedOnCompositorThread_MouseMove_WhenMouseDown) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
@@ skipping 54 matching lines @@
   EnableIdleTasks();
   scheduler_->DidHandleInputEventOnCompositorThread(
       FakeInputEvent(blink::WebInputEvent::MouseWheel),
       RendererScheduler::InputEventState::EVENT_FORWARDED_TO_MAIN_THREAD);
   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")));
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        EventConsumedOnCompositorThread_IgnoresKeyboardEvents) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
 
   EnableIdleTasks();
   scheduler_->DidHandleInputEventOnCompositorThread(
       FakeInputEvent(blink::WebInputEvent::KeyDown),
       RendererScheduler::InputEventState::EVENT_CONSUMED_BY_COMPOSITOR);
   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")));
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest,
        EventForwardedToMainThread_IgnoresKeyboardEvents) {
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "I1 D1 C1 D2 C2");
 
   EnableIdleTasks();
   scheduler_->DidHandleInputEventOnCompositorThread(
       FakeInputEvent(blink::WebInputEvent::KeyDown),
       RendererScheduler::InputEventState::EVENT_FORWARDED_TO_MAIN_THREAD);
   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")));
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
   // Note compositor tasks are not prioritized.
   scheduler_->DidHandleInputEventOnMainThread(
       FakeInputEvent(blink::WebInputEvent::KeyDown));
 }
 
 TEST_F(RendererSchedulerImplTest,
        TestMainthreadScrollingUseCaseDoesNotStarveDefaultTasks) {
   SimulateMainThreadGestureStart(TouchEventPolicy::DONT_SEND_TOUCH_START,
                                  blink::WebInputEvent::GestureScrollBegin);
   EnableIdleTasks();
@@ skipping 947 matching lines @@
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("L1"), std::string("D1")));
 
   // Emit a BeginMainFrame, and the loading task should get blocked.
   DoMainFrame();
   run_order.clear();
 
   PostTestTasks(&run_order, "L1 D1");
   RunUntilIdle();
 
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_TRUE(LoadingTasksSeemExpensive());
   EXPECT_FALSE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveLoadingTasksNotBlockedIfNoTouchHandler) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(false);
   DoMainFrame();
   SimulateExpensiveTasks(loading_task_runner_);
   ForceTouchStartToBeExpectedSoon();
   PostTestTasks(&run_order, "L1 D1");
   RunUntilIdle();
 
   EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_TRUE(LoadingTasksSeemExpensive());
   EXPECT_FALSE(TimerTasksSeemExpensive());
   EXPECT_FALSE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("L1"), std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_ANIMATION, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveTimerTaskBlocked_UseCase_NONE_PreviousCompositorGesture) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   DoMainFrame();
   SimulateExpensiveTasks(timer_task_runner_);
   ForceTouchStartToBeExpectedSoon();
 
   PostTestTasks(&run_order, "T1 D1");
   RunUntilIdle();
 
   EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_FALSE(LoadingTasksSeemExpensive());
   EXPECT_TRUE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveTimerTaskNotBlocked_UseCase_NONE_PreviousMainThreadGesture) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   DoMainFrame();
   SimulateExpensiveTasks(timer_task_runner_);
 
@@ skipping 14 matching lines @@
   PostTestTasks(&run_order, "T1 D1");
   RunUntilIdle();
 
   EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_FALSE(LoadingTasksSeemExpensive());
   EXPECT_TRUE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("T1"), std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_ANIMATION, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveTimerTaskBlocked_UseCase_COMPOSITOR_GESTURE) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   DoMainFrame();
   SimulateExpensiveTasks(timer_task_runner_);
   ForceTouchStartToBeExpectedSoon();
   scheduler_->DidAnimateForInputOnCompositorThread();
 
   PostTestTasks(&run_order, "T1 D1");
   RunUntilIdle();
 
   EXPECT_EQ(UseCase::COMPOSITOR_GESTURE,
             ForceUpdatePolicyAndGetCurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_FALSE(LoadingTasksSeemExpensive());
   EXPECT_TRUE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
-       ExpensiveTimerTaskNotBlockedIfDissalowed_UseCase_COMPOSITOR_GESTURE) {
+       ExpensiveTimerTaskNotBlockedIfDisallowed_UseCase_COMPOSITOR_GESTURE) {
   std::vector<std::string> run_order;
 
   scheduler_->SetExpensiveTaskBlockingAllowed(false);
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   DoMainFrame();
   SimulateExpensiveTasks(timer_task_runner_);
   ForceTouchStartToBeExpectedSoon();
   scheduler_->DidAnimateForInputOnCompositorThread();
 
   PostTestTasks(&run_order, "T1 D1");
   RunUntilIdle();
 
   EXPECT_EQ(UseCase::COMPOSITOR_GESTURE,
             ForceUpdatePolicyAndGetCurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_FALSE(LoadingTasksSeemExpensive());
   EXPECT_TRUE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("T1"),
                                               std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveTimerTaskBlocked_EvenIfBeginMainFrameNotExpectedSoon) {
   std::vector<std::string> run_order;
 
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   DoMainFrame();
   SimulateExpensiveTasks(timer_task_runner_);
   ForceTouchStartToBeExpectedSoon();
   scheduler_->BeginFrameNotExpectedSoon();
 
   PostTestTasks(&run_order, "T1 D1");
   RunUntilIdle();
 
   EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_FALSE(LoadingTasksSeemExpensive());
   EXPECT_TRUE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveLoadingTasksBlockedIfChildFrameNavigationExpected) {
   std::vector<std::string> run_order;
 
   DoMainFrame();
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateExpensiveTasks(loading_task_runner_);
   ForceTouchStartToBeExpectedSoon();
   scheduler_->AddPendingNavigation(
       blink::WebScheduler::NavigatingFrameType::kChildFrame);
 
   PostTestTasks(&run_order, "L1 D1");
   RunUntilIdle();
 
   // The expensive loading task gets blocked.
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveLoadingTasksNotBlockedIfMainFrameNavigationExpected) {
   std::vector<std::string> run_order;
 
   DoMainFrame();
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateExpensiveTasks(loading_task_runner_);
   ForceTouchStartToBeExpectedSoon();
@@ skipping 14 matching lines @@
 
   // After the nagigation has been cancelled, the expensive loading tasks should
   // get blocked.
   scheduler_->RemovePendingNavigation(
       blink::WebScheduler::NavigatingFrameType::kMainFrame);
   run_order.clear();
 
   PostTestTasks(&run_order, "L1 D1");
   RunUntilIdle();
 
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_TRUE(LoadingTasksSeemExpensive());
   EXPECT_FALSE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_EQ(0, NavigationTaskExpectedCount());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(
     RendererSchedulerImplTest,
     ExpensiveLoadingTasksNotBlockedIfMainFrameNavigationExpected_Multiple) {
   std::vector<std::string> run_order;
 
   DoMainFrame();
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateExpensiveTasks(loading_task_runner_);
@@ skipping 35 matching lines @@
 
 
   run_order.clear();
   scheduler_->RemovePendingNavigation(
       blink::WebScheduler::NavigatingFrameType::kMainFrame);
   // Navigation task expected ref count is now zero, the expensive loading tasks
   // should get blocked.
   PostTestTasks(&run_order, "L1 D1");
   RunUntilIdle();
 
-  EXPECT_EQ(RendererScheduler::UseCase::NONE, CurrentUseCase());
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::NONE, CurrentUseCase());
   EXPECT_TRUE(HaveSeenABeginMainframe());
   EXPECT_TRUE(LoadingTasksSeemExpensive());
   EXPECT_FALSE(TimerTasksSeemExpensive());
   EXPECT_TRUE(TouchStartExpectedSoon());
   EXPECT_EQ(0, NavigationTaskExpectedCount());
   EXPECT_THAT(run_order, testing::ElementsAre(std::string("D1")));
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest,
        ExpensiveLoadingTasksNotBlockedDuringMainThreadGestures) {
   std::vector<std::string> run_order;
 
   SimulateExpensiveTasks(loading_task_runner_);
 
   // Loading tasks should not be disabled during main thread user interactions.
   PostTestTasks(&run_order, "C1 L1");
 
   // Trigger main_thread_gesture UseCase
   SimulateMainThreadGestureStart(TouchEventPolicy::SEND_TOUCH_START,
                                  blink::WebInputEvent::GestureScrollBegin);
   RunUntilIdle();
-  EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
             CurrentUseCase());
 
   EXPECT_TRUE(LoadingTasksSeemExpensive());
   EXPECT_FALSE(TimerTasksSeemExpensive());
   EXPECT_THAT(run_order,
               testing::ElementsAre(std::string("C1"), std::string("L1")));
+  EXPECT_EQ(v8::PERFORMANCE_ANIMATION, RAILMode());
 }
 
 TEST_F(RendererSchedulerImplTest, ModeratelyExpensiveTimer_NotBlocked) {
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   SimulateMainThreadGestureStart(TouchEventPolicy::SEND_TOUCH_START,
                                  blink::WebInputEvent::TouchMove);
   RunUntilIdle();
   for (int i = 0; i < 20; i++) {
     simulate_timer_task_ran_ = false;
 
     cc::BeginFrameArgs begin_frame_args = cc::BeginFrameArgs::Create(
         BEGINFRAME_FROM_HERE, clock_->NowTicks(), base::TimeTicks(),
         base::TimeDelta::FromMilliseconds(16), cc::BeginFrameArgs::NORMAL);
     begin_frame_args.on_critical_path = false;
     scheduler_->WillBeginFrame(begin_frame_args);
 
     compositor_task_runner_->PostTask(
         FROM_HERE, base::Bind(&RendererSchedulerImplTest::
                                   SimulateMainThreadInputHandlingCompositorTask,
                               base::Unretained(this),
                               base::TimeDelta::FromMilliseconds(8)));
     timer_task_runner_->PostTask(
         FROM_HERE, base::Bind(&RendererSchedulerImplTest::SimulateTimerTask,
                               base::Unretained(this),
                               base::TimeDelta::FromMilliseconds(4)));
 
     RunUntilIdle();
     EXPECT_TRUE(simulate_timer_task_ran_) << " i = " << i;
-    EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+    EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
               CurrentUseCase())
         << " i = " << i;
     EXPECT_FALSE(LoadingTasksSeemExpensive()) << " i = " << i;
     EXPECT_FALSE(TimerTasksSeemExpensive()) << " i = " << i;
 
     base::TimeDelta time_till_next_frame =
         EstimatedNextFrameBegin() - clock_->NowTicks();
     if (time_till_next_frame > base::TimeDelta())
       clock_->Advance(time_till_next_frame);
   }
@@ skipping 18 matching lines @@
         base::Bind(&RendererSchedulerImplTest::SimulateMainThreadCompositorTask,
                    base::Unretained(this),
                    base::TimeDelta::FromMilliseconds(8)));
     timer_task_runner_->PostTask(
         FROM_HERE, base::Bind(&RendererSchedulerImplTest::SimulateTimerTask,
                               base::Unretained(this),
                               base::TimeDelta::FromMilliseconds(40)));
 
     RunUntilIdle();
     EXPECT_TRUE(simulate_timer_task_ran_) << " i = " << i;
-    EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE, CurrentUseCase())
+    EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
+              CurrentUseCase())
         << " i = " << i;
     EXPECT_FALSE(LoadingTasksSeemExpensive()) << " i = " << i;
     EXPECT_FALSE(TimerTasksSeemExpensive()) << " i = " << i;
 
     base::TimeDelta time_till_next_frame =
         EstimatedNextFrameBegin() - clock_->NowTicks();
     if (time_till_next_frame > base::TimeDelta())
       clock_->Advance(time_till_next_frame);
   }
 }
@@ skipping 17 matching lines @@
         FROM_HERE, base::Bind(&RendererSchedulerImplTest::
                                   SimulateMainThreadInputHandlingCompositorTask,
                               base::Unretained(this),
                               base::TimeDelta::FromMilliseconds(8)));
     timer_task_runner_->PostTask(
         FROM_HERE, base::Bind(&RendererSchedulerImplTest::SimulateTimerTask,
                               base::Unretained(this),
                               base::TimeDelta::FromMilliseconds(10)));
 
     RunUntilIdle();
-    EXPECT_EQ(RendererScheduler::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
+    EXPECT_EQ(RendererSchedulerImpl::UseCase::MAIN_THREAD_CUSTOM_INPUT_HANDLING,
               CurrentUseCase())
         << " i = " << i;
     EXPECT_FALSE(LoadingTasksSeemExpensive()) << " i = " << i;
     if (i == 0) {
       EXPECT_FALSE(TimerTasksSeemExpensive()) << " i = " << i;
     } else {
       EXPECT_TRUE(TimerTasksSeemExpensive()) << " i = " << i;
     }
     EXPECT_TRUE(simulate_timer_task_ran_) << " i = " << i;
 
@@ skipping 438 matching lines @@
   now += base::TimeDelta::FromMilliseconds(500);
   EXPECT_FALSE(idle_delegate->CanEnterLongIdlePeriod(now, &next_time_to_check));
   EXPECT_GE(next_time_to_check, base::TimeDelta());
 }
 
 TEST_F(RendererSchedulerImplTest, TestCompositorPolicy_TouchStartDuringFling) {
   scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
   scheduler_->DidAnimateForInputOnCompositorThread();
   // Note DidAnimateForInputOnCompositorThread does not by itself trigger a
   // policy update.
-  EXPECT_EQ(RendererScheduler::UseCase::COMPOSITOR_GESTURE,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::COMPOSITOR_GESTURE,
             ForceUpdatePolicyAndGetCurrentUseCase());
 
   // Make sure TouchStart causes a policy change.
   scheduler_->DidHandleInputEventOnCompositorThread(
       FakeInputEvent(blink::WebInputEvent::TouchStart),
       RendererScheduler::InputEventState::EVENT_FORWARDED_TO_MAIN_THREAD);
-  EXPECT_EQ(RendererScheduler::UseCase::TOUCHSTART,
+  EXPECT_EQ(RendererSchedulerImpl::UseCase::TOUCHSTART,
             ForceUpdatePolicyAndGetCurrentUseCase());
 }
 
 TEST_F(RendererSchedulerImplTest, SYNCHRONIZED_GESTURE_CompositingExpensive) {
   SimulateCompositorGestureStart(TouchEventPolicy::SEND_TOUCH_START);
 
   // With the compositor task taking 20ms, there is not enough time to run
   // other tasks in the same 16ms frame. To avoid starvation, compositing tasks
   // should therefore not get prioritized.
   std::vector<std::string> run_order;
@@ skipping 105 matching lines @@
         base::Bind(&RendererSchedulerImplTest::SimulatedCompositorTaskPending,
                    base::Unretained(this)));
     EXPECT_EQ(UseCase::MAIN_THREAD_GESTURE, CurrentUseCase()) << "i = " << i;
   }
 
   EXPECT_EQ(TaskQueue::HIGH_PRIORITY,
             scheduler_->CompositorTaskRunner()->GetQueuePriority());
   EXPECT_EQ(279u, run_order.size());
 }
 
+class MockRAILModeObserver : public RendererScheduler::RAILModeObserver {
+ public:
+  MOCK_METHOD1(OnRAILModeChanged, void(v8::RAILMode rail_mode));
+};
+
+TEST_F(RendererSchedulerImplTest, TestResponseRAILMode) {
+  MockRAILModeObserver observer;
+  scheduler_->SetRAILModeObserver(&observer);
+  EXPECT_CALL(observer, OnRAILModeChanged(v8::PERFORMANCE_RESPONSE));
+
+  scheduler_->SetHasVisibleRenderWidgetWithTouchHandler(true);
+  ForceTouchStartToBeExpectedSoon();
+  EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
+  EXPECT_EQ(v8::PERFORMANCE_RESPONSE, RAILMode());
+  scheduler_->SetRAILModeObserver(nullptr);
+}
+
+TEST_F(RendererSchedulerImplTest, TestAnimateRAILMode) {
+  MockRAILModeObserver observer;
+  scheduler_->SetRAILModeObserver(&observer);
+  EXPECT_CALL(observer, OnRAILModeChanged(v8::PERFORMANCE_ANIMATION)).Times(0);
+
+  EXPECT_FALSE(BeginFrameNotExpectedSoon());
+  EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
+  EXPECT_EQ(v8::PERFORMANCE_ANIMATION, RAILMode());
+  scheduler_->SetRAILModeObserver(nullptr);
+}
+
+TEST_F(RendererSchedulerImplTest, TestIdleRAILMode) {
+  MockRAILModeObserver observer;
+  scheduler_->SetRAILModeObserver(&observer);
+  EXPECT_CALL(observer, OnRAILModeChanged(v8::PERFORMANCE_ANIMATION));
+  EXPECT_CALL(observer, OnRAILModeChanged(v8::PERFORMANCE_IDLE));
+
+  scheduler_->SetAllRenderWidgetsHidden(true);
+  EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
+  EXPECT_EQ(v8::PERFORMANCE_IDLE, RAILMode());
+  scheduler_->SetAllRenderWidgetsHidden(false);
+  EXPECT_EQ(UseCase::NONE, ForceUpdatePolicyAndGetCurrentUseCase());
+  EXPECT_EQ(v8::PERFORMANCE_ANIMATION, RAILMode());
+  scheduler_->SetRAILModeObserver(nullptr);
+}
+
 }  // namespace scheduler