Prevent overlay scrollbars expand or hover together

cc/input/single_scrollbar_animation_controller_thinning_unittest.cc

 // Copyright 2013 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 "cc/input/scrollbar_animation_controller_thinning.h"
+#include "cc/input/single_scrollbar_animation_controller_thinning.h"
 
 #include "cc/layers/solid_color_scrollbar_layer_impl.h"
 #include "cc/test/fake_impl_task_runner_provider.h"
 #include "cc/test/fake_layer_tree_host_impl.h"
 #include "cc/test/geometry_test_utils.h"
 #include "cc/test/test_task_graph_runner.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using testing::AtLeast;
 using testing::Mock;
 using testing::NiceMock;
 using testing::_;
 
 namespace cc {
 namespace {
 
 // These constants are hard-coded and should match the values in
-// scrollbar_animation_controller_thinning.cc.
+// single_scrollbar_animation_controller_thinning.cc.
 const float kIdleThicknessScale = 0.4f;
 const float kDefaultMouseMoveDistanceToTriggerAnimation = 25.f;
 
-class MockScrollbarAnimationControllerClient
+class MockSingleScrollbarAnimationControllerClient
     : public ScrollbarAnimationControllerClient {
  public:
-  explicit MockScrollbarAnimationControllerClient(LayerTreeHostImpl* host_impl)
+  explicit MockSingleScrollbarAnimationControllerClient(
+      LayerTreeHostImpl* host_impl)
       : host_impl_(host_impl) {}
-  virtual ~MockScrollbarAnimationControllerClient() {}
+  virtual ~MockSingleScrollbarAnimationControllerClient() {}
 
   void PostDelayedScrollbarAnimationTask(const base::Closure& start_fade,
                                          base::TimeDelta delay) override {
     start_fade_ = start_fade;
     delay_ = delay;
   }
   void SetNeedsRedrawForScrollbarAnimation() override {}
   void SetNeedsAnimateForScrollbarAnimation() override {}
   ScrollbarSet ScrollbarsFor(int scroll_layer_id) const override {
     return host_impl_->ScrollbarsFor(scroll_layer_id);
   }
   MOCK_METHOD0(DidChangeScrollbarVisibility, void());
 
   base::Closure& start_fade() { return start_fade_; }
   base::TimeDelta& delay() { return delay_; }
 
  private:
   base::Closure start_fade_;
   base::TimeDelta delay_;
   LayerTreeHostImpl* host_impl_;
 };
 
-class ScrollbarAnimationControllerThinningTest : public testing::Test {
+class SingleScrollbarAnimationControllerThinningTest : public testing::Test {
  public:
-  ScrollbarAnimationControllerThinningTest()
+  SingleScrollbarAnimationControllerThinningTest()
       : host_impl_(&task_runner_provider_, &task_graph_runner_),
         client_(&host_impl_) {}
 
  protected:
   const base::TimeDelta kDelayBeforeStarting = base::TimeDelta::FromSeconds(2);
   const base::TimeDelta kResizeDelayBeforeStarting =
       base::TimeDelta::FromSeconds(5);
   const base::TimeDelta kFadeDuration = base::TimeDelta::FromSeconds(3);
   const base::TimeDelta kThinningDuration = base::TimeDelta::FromSeconds(2);
 
@@ skipping 21 matching lines @@
     scroll_layer->test_properties()->AddChild(std::move(scrollbar));
     clip_layer_->test_properties()->AddChild(std::move(scroll_layer));
     host_impl_.active_tree()->SetRootLayerForTesting(std::move(clip));
 
     scrollbar_layer_->SetScrollLayerId(scroll_layer_ptr->id());
     scrollbar_layer_->test_properties()->opacity_can_animate = true;
     clip_layer_->SetBounds(gfx::Size(100, 100));
     scroll_layer_ptr->SetBounds(gfx::Size(200, 200));
     host_impl_.active_tree()->BuildLayerListAndPropertyTreesForTesting();
 
-    scrollbar_controller_ = ScrollbarAnimationControllerThinning::Create(
-        scroll_layer_ptr->id(), &client_, kDelayBeforeStarting,
+    scrollbar_controller_ = SingleScrollbarAnimationControllerThinning::Create(
+        scroll_layer_ptr->id(), HORIZONTAL, &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<SingleScrollbarAnimationControllerThinning>
+      scrollbar_controller_;
   LayerImpl* clip_layer_;
   SolidColorScrollbarLayerImpl* scrollbar_layer_;
-  NiceMock<MockScrollbarAnimationControllerClient> client_;
+  NiceMock<MockSingleScrollbarAnimationControllerClient> client_;
 };
 
 // Check initialization of scrollbar. Should start off invisible and thin.
-TEST_F(ScrollbarAnimationControllerThinningTest, Idle) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, Idle) {
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
-  EXPECT_FLOAT_EQ(0.4f, scrollbar_layer_->thumb_thickness_scale_factor());
+  EXPECT_FLOAT_EQ(kIdleThicknessScale,
+                  scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Check that scrollbar appears again when the layer becomes scrollable.
-TEST_F(ScrollbarAnimationControllerThinningTest, AppearOnResize) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, AppearOnResize) {
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
 
   // Make the Layer non-scrollable, scrollbar disappears.
   clip_layer_->SetBounds(gfx::Size(200, 200));
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
 
   // Make the layer scrollable, scrollbar appears again.
   clip_layer_->SetBounds(gfx::Size(100, 100));
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
 }
 
 // Check that scrollbar disappears when the layer becomes non-scrollable.
-TEST_F(ScrollbarAnimationControllerThinningTest, HideOnResize) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, 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());
 
@@ skipping 11 matching lines @@
 
   scrollbar_controller_->DidScrollBegin();
 
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
 
   scrollbar_controller_->DidScrollEnd();
 }
 
 // Scroll content. Confirm the scrollbar appears and fades out.
-TEST_F(ScrollbarAnimationControllerThinningTest, BasicAppearAndFadeOut) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, BasicAppearAndFadeOut) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Scrollbar should be invisible by default.
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
 
   // Scrollbar should appear only on scroll update.
   scrollbar_controller_->DidScrollBegin();
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
 
@@ skipping 11 matching lines @@
   // Scrollbar should fade out over kFadeDuration.
   scrollbar_controller_->Animate(time);
   time += kFadeDuration;
   scrollbar_controller_->Animate(time);
 
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
 }
 
 // Scroll content. Move the mouse near the scrollbar and confirm it becomes
 // thick. Ensure it fades out after that.
-TEST_F(ScrollbarAnimationControllerThinningTest, MoveNearAndFadeOut) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, MoveNearAndFadeOut) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // An animation should have been enqueued.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
 
   // Now move the mouse near the scrollbar. This should cancel the currently
   // queued fading animation and start animating thickness.
-  scrollbar_controller_->DidMouseMoveNear(1);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 1);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
   EXPECT_TRUE(client_.start_fade().IsCancelled());
 
   // Scrollbar should become thick.
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Once the thickening animation is complete, it should enqueue the delayed
   // fade animation.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_FALSE(client_.start_fade().IsCancelled());
 }
 
 // Scroll content. Move the mouse over the scrollbar and confirm it becomes
 // thick. Ensure it fades out after that.
-TEST_F(ScrollbarAnimationControllerThinningTest, MoveOverAndFadeOut) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, MoveOverAndFadeOut) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // An animation should have been enqueued.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
 
   // Now move the mouse over the scrollbar. This should cancel the currently
   // queued fading animation and start animating thickness.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
   EXPECT_TRUE(client_.start_fade().IsCancelled());
 
   // Scrollbar should become thick.
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Once the thickening animation is complete, it should enqueue the delayed
   // fade animation.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_FALSE(client_.start_fade().IsCancelled());
 }
 
 // Make sure a scrollbar captured before the thickening animation doesn't try
 // to fade out.
-TEST_F(ScrollbarAnimationControllerThinningTest,
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
        DontFadeWhileCapturedBeforeThick) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // An animation should have been enqueued.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
 
   // Now move the mouse over the scrollbar and capture it. It should become
   // thick without need for an animation.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->DidMouseDown();
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // The fade animation should have been cancelled.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_TRUE(client_.start_fade().IsCancelled());
 }
 
 // Make sure a scrollbar captured after a thickening animation doesn't try to
 // fade out.
-TEST_F(ScrollbarAnimationControllerThinningTest, DontFadeWhileCaptured) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, DontFadeWhileCaptured) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // An animation should have been enqueued.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
 
   // Now move the mouse over the scrollbar and animate it until it's thick.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Since the scrollbar became thick, it should have queued up a fade.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_FALSE(client_.start_fade().IsCancelled());
 
   // Make sure capturing the scrollbar stops the fade.
   scrollbar_controller_->DidMouseDown();
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_TRUE(client_.start_fade().IsCancelled());
 }
 
 // Make sure releasing a captured scrollbar causes it to fade out.
-TEST_F(ScrollbarAnimationControllerThinningTest, FadeAfterReleased) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, FadeAfterReleased) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // An animation should have been enqueued.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
 
   // Now move the mouse over the scrollbar and capture it.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->DidMouseDown();
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Since the scrollbar became thick, it should have queued up a fade.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_TRUE(client_.start_fade().IsCancelled());
 
   scrollbar_controller_->DidMouseUp();
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_FALSE(client_.start_fade().IsCancelled());
 }
 
 // Make sure moving near a scrollbar while it's fading out causes it to reset
 // the opacity and thicken.
-TEST_F(ScrollbarAnimationControllerThinningTest, MoveNearScrollbarWhileFading) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
+       MoveNearScrollbarWhileFading) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // An animation should have been enqueued. Start it.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
   client_.start_fade().Run();
 
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
 
   // Proceed half way through the fade out animation.
   time += kFadeDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(0.5f, scrollbar_layer_->Opacity());
 
   // Now move the mouse near the scrollbar. It should reset opacity to 1
   // instantly and start animating to thick.
-  scrollbar_controller_->DidMouseMoveNear(1);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 1);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Make sure capturing a scrollbar while it's fading out causes it to reset the
 // opacity and thicken instantly.
-TEST_F(ScrollbarAnimationControllerThinningTest, CaptureScrollbarWhileFading) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
+       CaptureScrollbarWhileFading) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // Move mouse over the scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // A fade animation should have been enqueued. Start it.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
   client_.start_fade().Run();
 
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
 
   // Proceed half way through the fade out animation.
   time += kFadeDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(0.5f, scrollbar_layer_->Opacity());
 
   // Now capture the scrollbar. It should reset opacity to 1 instantly.
   scrollbar_controller_->DidMouseDown();
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Make sure we can't capture scrollbar that's completely faded out
-TEST_F(ScrollbarAnimationControllerThinningTest, TestCantCaptureWhenFaded) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
+       TestCantCaptureWhenFaded) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // Move mouse over the scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // A fade animation should have been enqueued. Start it.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
   EXPECT_FALSE(client_.start_fade().is_null());
   client_.start_fade().Run();
@@ skipping 17 matching lines @@
 
   // Similarly, releasing the scrollbar should have no effect.
   scrollbar_controller_->DidMouseUp();
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
   EXPECT_TRUE(client_.start_fade().is_null());
 }
 
 // Initiate a scroll when the pointer is already near the scrollbar. It should
 // appear thick and remain thick.
-TEST_F(ScrollbarAnimationControllerThinningTest, ScrollWithMouseNear) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, ScrollWithMouseNear) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  scrollbar_controller_->DidMouseMoveNear(1);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 1);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
 
   // Since the scrollbar isn't visible yet (because we haven't scrolled), we
   // shouldn't have applied the thickening.
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   scrollbar_controller_->DidScrollBegin();
@@ skipping 14 matching lines @@
 
   // Scrollbar should still be thick, even though the scrollbar fades out.
   time += kFadeDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Move the pointer near the scrollbar. Confirm it gets thick and narrow when
 // moved away.
-TEST_F(ScrollbarAnimationControllerThinningTest, MouseNear) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, MouseNear) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
-  scrollbar_controller_->DidMouseMoveNear(1);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 1);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Should animate to thickened.
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Subsequent moves within the nearness threshold should not change anything.
-  scrollbar_controller_->DidMouseMoveNear(2);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 2);
   scrollbar_controller_->Animate(time);
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Now move away from bar.
   scrollbar_controller_->DidMouseMoveNear(
-      kDefaultMouseMoveDistanceToTriggerAnimation);
+      HORIZONTAL, kDefaultMouseMoveDistanceToTriggerAnimation);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Move the pointer over the scrollbar. Make sure it gets thick that it gets
 // thin when moved away.
-TEST_F(ScrollbarAnimationControllerThinningTest, MouseOver) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, MouseOver) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Should animate to thickened.
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Subsequent moves should not change anything.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Moving off the scrollbar but still withing the "near" threshold should do
   // nothing.
   scrollbar_controller_->DidMouseMoveNear(
-      kDefaultMouseMoveDistanceToTriggerAnimation - 1.f);
+      HORIZONTAL, kDefaultMouseMoveDistanceToTriggerAnimation - 1.f);
   scrollbar_controller_->Animate(time);
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Now move away from bar.
   scrollbar_controller_->DidMouseMoveNear(
-      kDefaultMouseMoveDistanceToTriggerAnimation);
+      HORIZONTAL, kDefaultMouseMoveDistanceToTriggerAnimation);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // First move the pointer over the scrollbar off of it. Make sure the thinning
 // animation kicked off in DidMouseMoveOffScrollbar gets overridden by the
 // thickening animation in the DidMouseMoveNear call.
-TEST_F(ScrollbarAnimationControllerThinningTest,
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
        MouseNearThenAwayWhileAnimating) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Should animate to thickened.
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // This is tricky. The DidMouseLeave() is sent before the
   // subsequent DidMouseMoveNear(), if the mouse moves in that direction.
   // This results in the thumb thinning. We want to make sure that when the
   // thumb starts expanding it doesn't first narrow to the idle thinness.
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->DidMouseLeave();
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Let the animation run half of the way through the thinning animation.
   time += kThinningDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f - (1.0f - kIdleThicknessScale) / 2.0f,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Now we get a notification for the mouse moving over the scroller. The
   // animation is reset to the thickening direction but we won't start
   // thickening until the new animation catches up to the current thickness.
-  scrollbar_controller_->DidMouseMoveNear(1);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 1);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f - (1.0f - kIdleThicknessScale) / 2.0f,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Until we reach the half way point, the animation will have no effect.
   time += kThinningDuration / 4;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f - (1.0f - kIdleThicknessScale) / 2.0f,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
@@ skipping 11 matching lines @@
 
   // And all the way to the end.
   time += kThinningDuration / 4;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // First move the pointer on the scrollbar, then press it, then away.
 // Confirm that the bar gets thick. Then mouse up. Confirm that
 // the bar gets thin.
-TEST_F(ScrollbarAnimationControllerThinningTest,
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
        MouseCaptureAndReleaseOutOfBar) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Move over the scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += kFadeDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Capture
   scrollbar_controller_->DidMouseDown();
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Should stay thick for a while.
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
 
   // Move outside the "near" threshold. Because the scrollbar is captured it
   // should remain thick.
   scrollbar_controller_->DidMouseMoveNear(
-      kDefaultMouseMoveDistanceToTriggerAnimation);
+      HORIZONTAL, kDefaultMouseMoveDistanceToTriggerAnimation);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Release.
   scrollbar_controller_->DidMouseUp();
 
   // Should become thin.
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // First move the pointer on the scrollbar, then press it, then away.  Confirm
 // that the bar gets thick. Then move point on the scrollbar and mouse up.
 // Confirm that the bar stays thick.
-TEST_F(ScrollbarAnimationControllerThinningTest, MouseCaptureAndReleaseOnBar) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
+       MouseCaptureAndReleaseOnBar) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Move over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Capture. Nothing should change.
   scrollbar_controller_->DidMouseDown();
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->Animate(time);
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Move away from scrollbar. Nothing should change.
   scrollbar_controller_->DidMouseMoveNear(
-      kDefaultMouseMoveDistanceToTriggerAnimation);
+      HORIZONTAL, kDefaultMouseMoveDistanceToTriggerAnimation);
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->Animate(time);
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Move over scrollbar and release. Since we're near the scrollbar, it should
   // remain thick.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->DidMouseUp();
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->Animate(time);
   time += base::TimeDelta::FromSeconds(10);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Move mouse on scrollbar and capture then move out of window. Confirm that
 // the bar stays thick.
-TEST_F(ScrollbarAnimationControllerThinningTest,
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
        MouseCapturedAndExitWindowFromScrollbar) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Move mouse over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(0);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 0);
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Capture.
   scrollbar_controller_->DidMouseDown();
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Move out of window. Since the scrollbar is capture, it shouldn't change in
   // any way.
   scrollbar_controller_->DidMouseLeave();
   scrollbar_controller_->Animate(time);
   time += kThinningDuration;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Tests that the thickening/thinning effects are animated.
-TEST_F(ScrollbarAnimationControllerThinningTest, ThicknessAnimated) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, ThicknessAnimated) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Move mouse near scrollbar. Test that at half the duration time, the
   // thickness is half way through its animation.
-  scrollbar_controller_->DidMouseMoveNear(1);
+  scrollbar_controller_->DidMouseMoveNear(HORIZONTAL, 1);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   time += kThinningDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(kIdleThicknessScale + (1.0f - kIdleThicknessScale) / 2.0f,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   time += kThinningDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   // Move mouse away from scrollbar. Same check.
   time += base::TimeDelta::FromSeconds(1);
   scrollbar_controller_->DidMouseMoveNear(
-      kDefaultMouseMoveDistanceToTriggerAnimation);
+      HORIZONTAL, kDefaultMouseMoveDistanceToTriggerAnimation);
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->thumb_thickness_scale_factor());
 
   time += kThinningDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(1.0f - (1.0f - kIdleThicknessScale) / 2.0f,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 
   time += kThinningDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   scrollbar_layer_->thumb_thickness_scale_factor());
 }
 
 // Tests that main thread scroll updates immediatley queue a fade animation
 // without requiring a ScrollEnd.
-TEST_F(ScrollbarAnimationControllerThinningTest, MainThreadScrollQueuesFade) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
+       MainThreadScrollQueuesFade) {
   ASSERT_TRUE(client_.start_fade().is_null());
 
   // A ScrollUpdate without a ScrollBegin indicates a main thread scroll update
   // so we should schedule a fade animation without waiting for a ScrollEnd
   // (which will never come).
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
 
   client_.start_fade().Reset();
 
   // If we got a ScrollBegin, we shouldn't schedule the fade animation until we
   // get a corresponding ScrollEnd.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_TRUE(client_.start_fade().is_null());
   scrollbar_controller_->DidScrollEnd();
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
 }
 
 // Make sure that if the scroll update is as a result of a resize, we use the
 // resize delay time instead of the default one.
-TEST_F(ScrollbarAnimationControllerThinningTest, ResizeFadeDuration) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, ResizeFadeDuration) {
   ASSERT_TRUE(client_.delay().is_zero());
 
   scrollbar_controller_->DidScrollUpdate(true);
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_EQ(kResizeDelayBeforeStarting, client_.delay());
 
   client_.delay() = base::TimeDelta();
 
   // We should use the gesture delay rather than the resize delay if we're in a
   // gesture scroll, even if the resize param is set.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(true);
   scrollbar_controller_->DidScrollEnd();
 
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
 }
 
 // Tests that the fade effect is animated.
-TEST_F(ScrollbarAnimationControllerThinningTest, FadeAnimated) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest, FadeAnimated) {
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   scrollbar_controller_->DidScrollEnd();
 
   // Appearance is instant.
   EXPECT_FLOAT_EQ(1.0f, scrollbar_layer_->Opacity());
 
   // An animation should have been enqueued.
   EXPECT_EQ(kDelayBeforeStarting, client_.delay());
@@ skipping 10 matching lines @@
   time += kFadeDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(0.5f, scrollbar_layer_->Opacity());
 
   time += kFadeDuration / 2;
   scrollbar_controller_->Animate(time);
   EXPECT_FLOAT_EQ(0.0f, scrollbar_layer_->Opacity());
 }
 
 // Tests that the controller tells the client when the scrollbars hide/show.
-TEST_F(ScrollbarAnimationControllerThinningTest, NotifyChangedVisibility) {
+TEST_F(SingleScrollbarAnimationControllerThinningTest,
+       NotifyChangedVisibility) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   EXPECT_CALL(client_, DidChangeScrollbarVisibility()).Times(1);
   // Scroll to make the scrollbars visible.
   scrollbar_controller_->DidScrollBegin();
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_FALSE(scrollbar_controller_->ScrollbarsHidden());
   Mock::VerifyAndClearExpectations(&client_);
 
@@ skipping 28 matching lines @@
   // Calling DidScrollUpdate without a begin (i.e. update from commit) should
   // also notify.
   EXPECT_CALL(client_, DidChangeScrollbarVisibility()).Times(1);
   scrollbar_controller_->DidScrollUpdate(false);
   EXPECT_FALSE(scrollbar_controller_->ScrollbarsHidden());
   Mock::VerifyAndClearExpectations(&client_);
 }
 
 }  // namespace
 }  // namespace cc