Merge Compositor's ScrollbarAnimationControllers into single class

cc/input/scrollbar_animation_controller_unittest.cc

Index: cc/input/scrollbar_animation_controller_unittest.cc
diff --git a/cc/input/scrollbar_animation_controller_thinning_unittest.cc b/cc/input/scrollbar_animation_controller_unittest.cc
similarity index 68%
rename from cc/input/scrollbar_animation_controller_thinning_unittest.cc
rename to cc/input/scrollbar_animation_controller_unittest.cc
index f238b8b986b051de542409b8bd8b1d02f898f090..288cf65630f9e51ef6049992b6ecd265b31e2fb9 100644
--- a/cc/input/scrollbar_animation_controller_thinning_unittest.cc
+++ b/cc/input/scrollbar_animation_controller_unittest.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "cc/input/scrollbar_animation_controller_thinning.h"
+#include "cc/input/scrollbar_animation_controller.h"
 
 #include "cc/layers/solid_color_scrollbar_layer_impl.h"
 #include "cc/test/fake_impl_task_runner_provider.h"
@@ -110,15 +110,16 @@ class ScrollbarAnimationControllerThinningTest : public testing::Test {
     scroll_layer_ptr->SetBounds(gfx::Size(200, 200));
     host_impl_.active_tree()->BuildLayerListAndPropertyTreesForTesting();
 
-    scrollbar_controller_ = ScrollbarAnimationControllerThinning::Create(
-        scroll_layer_ptr->id(), &client_, kDelayBeforeStarting,
-        kResizeDelayBeforeStarting, kFadeDuration, kThinningDuration);
+    scrollbar_controller_ = ScrollbarAnimationController::
+        CreateScrollbarAnimationControllerThinning(
+            scroll_layer_ptr->id(), &client_, kDelayBeforeStarting,
+            kResizeDelayBeforeStarting, kFadeDuration, kThinningDuration);
   }
 
   FakeImplTaskRunnerProvider task_runner_provider_;
   TestTaskGraphRunner task_graph_runner_;
   FakeLayerTreeHostImpl host_impl_;
-  std::unique_ptr<ScrollbarAnimationControllerThinning> scrollbar_controller_;
+  std::unique_ptr<ScrollbarAnimationController> scrollbar_controller_;
   LayerImpl* clip_layer_;
   SolidColorScrollbarLayerImpl* v_scrollbar_layer_;
   SolidColorScrollbarLayerImpl* h_scrollbar_layer_;
@@ -617,7 +618,6 @@ TEST_F(ScrollbarAnimationControllerThinningTest, ScrollWithMouseNear) {
   // An animation for the fade should be either null or cancelled, since
   // mouse is still near the scrollbar.
   scrollbar_controller_->DidScrollEnd();
-  EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_TRUE(client_.start_fade().is_null() ||
               client_.start_fade().IsCancelled());
 
@@ -972,5 +972,491 @@ TEST_F(ScrollbarAnimationControllerThinningTest, MouseLeaveFadeOut) {
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
 }
 
+class ScrollbarAnimationControllerLinearFadeTest
+    : public testing::Test,
+      public ScrollbarAnimationControllerClient {
+ public:
+  ScrollbarAnimationControllerLinearFadeTest()
+      : host_impl_(&task_runner_provider_, &task_graph_runner_),
+        did_request_redraw_(false),
+        did_request_animate_(false) {}
+
+  void PostDelayedScrollbarAnimationTask(const base::Closure& start_fade,
+                                         base::TimeDelta delay) override {
+    start_fade_ = start_fade;
+    delay_ = delay;
+  }
+  void SetNeedsRedrawForScrollbarAnimation() override {
+    did_request_redraw_ = true;
+  }
+  void SetNeedsAnimateForScrollbarAnimation() override {
+    did_request_animate_ = true;
+  }
+  ScrollbarSet ScrollbarsFor(int scroll_layer_id) const override {
+    return host_impl_.ScrollbarsFor(scroll_layer_id);
+  }
+  void DidChangeScrollbarVisibility() override {}
+
+ protected:
+  void SetUp() override {
+    const int kThumbThickness = 10;
+    const int kTrackStart = 0;
+    const bool kIsLeftSideVerticalScrollbar = false;
+    const bool kIsOverlayScrollbar = true;  // Allow opacity animations.
+
+    std::unique_ptr<LayerImpl> scroll_layer =
+        LayerImpl::Create(host_impl_.active_tree(), 1);
+    std::unique_ptr<SolidColorScrollbarLayerImpl> scrollbar =
+        SolidColorScrollbarLayerImpl::Create(
+            host_impl_.active_tree(), 2, orientation(), kThumbThickness,
+            kTrackStart, kIsLeftSideVerticalScrollbar, kIsOverlayScrollbar);
+    scrollbar_layer_ = scrollbar.get();
+    scrollbar_layer_->test_properties()->opacity_can_animate = true;
+    std::unique_ptr<LayerImpl> clip =
+        LayerImpl::Create(host_impl_.active_tree(), 3);
+    clip_layer_ = clip.get();
+    scroll_layer->SetScrollClipLayer(clip_layer_->id());
+    LayerImpl* scroll_layer_ptr = scroll_layer.get();
+    scroll_layer->test_properties()->AddChild(std::move(scrollbar));
+    clip->test_properties()->AddChild(std::move(scroll_layer));
+    host_impl_.active_tree()->SetRootLayerForTesting(std::move(clip));
+
+    scrollbar_layer_->SetScrollLayerId(scroll_layer_ptr->id());
+    clip_layer_->SetBounds(gfx::Size(100, 100));
+    scroll_layer_ptr->SetBounds(gfx::Size(200, 200));
+    host_impl_.active_tree()->BuildLayerListAndPropertyTreesForTesting();
+
+    scrollbar_controller_ = ScrollbarAnimationController::
+        CreateScrollbarAnimationControllerLinearFade(
+            scroll_layer_ptr->id(), this, base::TimeDelta::FromSeconds(2),
+            base::TimeDelta::FromSeconds(5), base::TimeDelta::FromSeconds(3));
+  }
+
+  virtual ScrollbarOrientation orientation() const { return HORIZONTAL; }
+
+  FakeImplTaskRunnerProvider task_runner_provider_;
+  TestTaskGraphRunner task_graph_runner_;
+  FakeLayerTreeHostImpl host_impl_;
+  std::unique_ptr<ScrollbarAnimationController> scrollbar_controller_;
+  LayerImpl* clip_layer_;
+  SolidColorScrollbarLayerImpl* scrollbar_layer_;
+
+  base::Closure start_fade_;
+  base::TimeDelta delay_;
+  bool did_request_redraw_;
+  bool did_request_animate_;
+};
+
+class VerticalScrollbarAnimationControllerLinearFadeTest
+    : public ScrollbarAnimationControllerLinearFadeTest {
+ protected:
+  ScrollbarOrientation orientation() const override { return VERTICAL; }
+};
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest, DelayAnimationOnResize) {
+  scrollbar_layer_->layer_tree_impl()
+      ->property_trees()
+      ->effect_tree.OnOpacityAnimated(0.0f,
+                                      scrollbar_layer_->effect_tree_index(),
+                                      scrollbar_layer_->layer_tree_impl());
+  scrollbar_controller_->DidScrollBegin();
+  scrollbar_controller_->DidScrollUpdate(true);
+  scrollbar_controller_->DidScrollEnd();
+  // Normal Animation delay of 2 seconds.
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+  EXPECT_EQ(delay_, base::TimeDelta::FromSeconds(2));
+
+  scrollbar_layer_->layer_tree_impl()
+      ->property_trees()
+      ->effect_tree.OnOpacityAnimated(0.0f,
+                                      scrollbar_layer_->effect_tree_index(),
+                                      scrollbar_layer_->layer_tree_impl());
+  scrollbar_controller_->DidScrollUpdate(true);
+  // Delay animation on resize to 5 seconds.
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+  EXPECT_EQ(delay_, base::TimeDelta::FromSeconds(5));
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest, HiddenInBegin) {
+  scrollbar_layer_->layer_tree_impl()
+      ->property_trees()
+      ->effect_tree.OnOpacityAnimated(0.0f,
+                                      scrollbar_layer_->effect_tree_index(),
+                                      scrollbar_layer_->layer_tree_impl());
+  scrollbar_controller_->Animate(base::TimeTicks());
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest,
+       HiddenAfterNonScrollingGesture) {
+  scrollbar_layer_->layer_tree_impl()
+      ->property_trees()
+      ->effect_tree.OnOpacityAnimated(0.0f,
+                                      scrollbar_layer_->effect_tree_index(),
+                                      scrollbar_layer_->layer_tree_impl());
+  scrollbar_controller_->DidScrollBegin();
+
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(100);
+  scrollbar_controller_->Animate(time);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+  scrollbar_controller_->DidScrollEnd();
+
+  EXPECT_TRUE(start_fade_.Equals(base::Closure()));
+
+  time += base::TimeDelta::FromSeconds(100);
+  scrollbar_controller_->Animate(time);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest, HideOnResize) {
+  LayerImpl* scroll_layer = host_impl_.active_tree()->LayerById(1);
+  ASSERT_TRUE(scroll_layer);
+  EXPECT_EQ(gfx::Size(200, 200), scroll_layer->bounds());
+
+  EXPECT_EQ(HORIZONTAL, scrollbar_layer_->orientation());
+
+  // Shrink along X axis, horizontal scrollbar should appear.
+  clip_layer_->SetBounds(gfx::Size(100, 200));
+  EXPECT_EQ(gfx::Size(100, 200), clip_layer_->bounds());
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+
+  // Shrink along Y axis and expand along X, horizontal scrollbar
+  // should disappear.
+  clip_layer_->SetBounds(gfx::Size(200, 100));
+  EXPECT_EQ(gfx::Size(200, 100), clip_layer_->bounds());
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+}
+
+TEST_F(VerticalScrollbarAnimationControllerLinearFadeTest, HideOnResize) {
+  LayerImpl* scroll_layer = host_impl_.active_tree()->LayerById(1);
+  ASSERT_TRUE(scroll_layer);
+  EXPECT_EQ(gfx::Size(200, 200), scroll_layer->bounds());
+
+  EXPECT_EQ(VERTICAL, scrollbar_layer_->orientation());
+
+  // Shrink along X axis, vertical scrollbar should remain invisible.
+  clip_layer_->SetBounds(gfx::Size(100, 200));
+  EXPECT_EQ(gfx::Size(100, 200), clip_layer_->bounds());
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+
+  // Shrink along Y axis and expand along X, vertical scrollbar should appear.
+  clip_layer_->SetBounds(gfx::Size(200, 100));
+  EXPECT_EQ(gfx::Size(200, 100), clip_layer_->bounds());
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest,
+       HideOnUserNonScrollableHorz) {
+  EXPECT_EQ(HORIZONTAL, scrollbar_layer_->orientation());
+
+  LayerImpl* scroll_layer = host_impl_.active_tree()->LayerById(1);
+  ASSERT_TRUE(scroll_layer);
+  scroll_layer->set_user_scrollable_horizontal(false);
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest,
+       ShowOnUserNonScrollableVert) {
+  EXPECT_EQ(HORIZONTAL, scrollbar_layer_->orientation());
+
+  LayerImpl* scroll_layer = host_impl_.active_tree()->LayerById(1);
+  ASSERT_TRUE(scroll_layer);
+  scroll_layer->set_user_scrollable_vertical(false);
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+}
+
+TEST_F(VerticalScrollbarAnimationControllerLinearFadeTest,
+       HideOnUserNonScrollableVert) {
+  EXPECT_EQ(VERTICAL, scrollbar_layer_->orientation());
+
+  LayerImpl* scroll_layer = host_impl_.active_tree()->LayerById(1);
+  ASSERT_TRUE(scroll_layer);
+  scroll_layer->set_user_scrollable_vertical(false);
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+}
+
+TEST_F(VerticalScrollbarAnimationControllerLinearFadeTest,
+       ShowOnUserNonScrollableHorz) {
+  EXPECT_EQ(VERTICAL, scrollbar_layer_->orientation());
+
+  LayerImpl* scroll_layer = host_impl_.active_tree()->LayerById(1);
+  ASSERT_TRUE(scroll_layer);
+  scroll_layer->set_user_scrollable_horizontal(false);
+
+  scrollbar_controller_->DidScrollBegin();
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest, AwakenByScrollingGesture) {
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollBegin();
+  EXPECT_FALSE(did_request_animate_);
+
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  EXPECT_TRUE(start_fade_.Equals(base::Closure()));
+
+  time += base::TimeDelta::FromSeconds(100);
+
+  scrollbar_controller_->Animate(time);
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+  scrollbar_controller_->DidScrollEnd();
+  EXPECT_FALSE(did_request_animate_);
+  start_fade_.Run();
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+
+  time += base::TimeDelta::FromSeconds(2);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+
+  scrollbar_controller_->DidScrollBegin();
+  scrollbar_controller_->DidScrollUpdate(false);
+  scrollbar_controller_->DidScrollEnd();
+
+  start_fade_.Run();
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+
+  time += base::TimeDelta::FromSeconds(2);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest, AwakenByProgrammaticScroll) {
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FALSE(did_request_animate_);
+
+  start_fade_.Run();
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FALSE(did_request_animate_);
+
+  start_fade_.Run();
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  time += base::TimeDelta::FromSeconds(2);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollUpdate(false);
+  start_fade_.Run();
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest,
+       AnimationPreservedByNonScrollingGesture) {
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollUpdate(false);
+  start_fade_.Run();
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollBegin();
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollEnd();
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
+}
+
+TEST_F(ScrollbarAnimationControllerLinearFadeTest,
+       AnimationOverriddenByScrollingGesture) {
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FALSE(did_request_animate_);
+  start_fade_.Run();
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  scrollbar_controller_->DidScrollBegin();
+  EXPECT_FLOAT_EQ(2.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->Animate(time);
+  EXPECT_TRUE(did_request_animate_);
+  did_request_animate_ = false;
+  EXPECT_FLOAT_EQ(1.0f / 3.0f, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollUpdate(false);
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(1, scrollbar_layer_->Opacity());
+
+  time += base::TimeDelta::FromSeconds(1);
+  scrollbar_controller_->DidScrollEnd();
+  EXPECT_FALSE(did_request_animate_);
+  EXPECT_FLOAT_EQ(1, scrollbar_layer_->Opacity());
+}
+
 }  // namespace
 }  // namespace cc