Don't fade in overlay scrollbar when user interacting the content under scrollbar.

cc/input/scrollbar_animation_controller_unittest.cc

Index: cc/input/scrollbar_animation_controller_unittest.cc
diff --git a/cc/input/scrollbar_animation_controller_unittest.cc b/cc/input/scrollbar_animation_controller_unittest.cc
index e1cb8957e9702ab994ca3bb60787981d99125b0c..573dcc19236d33df4cef619234c7a3a924683357 100644
--- a/cc/input/scrollbar_animation_controller_unittest.cc
+++ b/cc/input/scrollbar_animation_controller_unittest.cc
@@ -717,13 +717,28 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest, TestCantCaptureWhenFaded) {
                   h_scrollbar_layer_->thumb_thickness_scale_factor());
   EXPECT_TRUE(client_.start_fade().is_null());
 
-  // Similarly, releasing the scrollbar should have no effect.
+  // Similarly, releasing the scrollbar should have no effect but trigger a fade
+  // in.
   scrollbar_controller_->DidMouseUp();
   ExpectScrollbarsOpacity(0);
   EXPECT_FLOAT_EQ(1, v_scrollbar_layer_->thumb_thickness_scale_factor());
   EXPECT_FLOAT_EQ(kIdleThicknessScale,
                   h_scrollbar_layer_->thumb_thickness_scale_factor());
-  EXPECT_TRUE(client_.start_fade().is_null());
+
+  // An fade in animation should have been enqueued.
+  EXPECT_FALSE(client_.start_fade().is_null());
+  EXPECT_FALSE(client_.start_fade().IsCancelled());
+  EXPECT_EQ(kFadeDelay, client_.delay());
+
+  // Play the delay animation.
+  client_.start_fade().Run();
+  EXPECT_TRUE(client_.start_fade().IsCancelled());
+
+  scrollbar_controller_->Animate(time);
+  time += kFadeDuration;
+  scrollbar_controller_->Animate(time);
+
+  EXPECT_FALSE(scrollbar_controller_->ScrollbarsHidden());
 }
 
 // Initiate a scroll when the pointer is already near the scrollbar. It should
@@ -1093,7 +1108,7 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest, BasicMouseHoverFadeIn) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse hover the fade in scrollbar region of scrollbar.
+  // Move mouse over the fade in scrollbar region of scrollbar.
   scrollbar_controller_->DidMouseMove(
       NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
 
@@ -1127,7 +1142,7 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse hover the fade in scrollbar region of scrollbar.
+  // Move mouse over the fade in scrollbar region of scrollbar.
   scrollbar_controller_->DidMouseMove(
       NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
 
@@ -1152,7 +1167,7 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse hover the fade in scrollbar region of scrollbar.
+  // Move mouse over the fade in scrollbar region of scrollbar.
   scrollbar_controller_->DidMouseMove(
       NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
 
@@ -1176,7 +1191,7 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse hover the fade in scrollbar region of scrollbar.
+  // Move mouse over the fade in scrollbar region of scrollbar.
   scrollbar_controller_->DidMouseMove(
       NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
 
@@ -1190,10 +1205,59 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   EXPECT_TRUE(client_.start_fade().is_null() ||
               client_.start_fade().IsCancelled());
 
-  // Move mouse hover the fade in scrollbar region of scrollbar.
+  // Move mouse over the fade in scrollbar region of scrollbar.
+  scrollbar_controller_->DidMouseMove(
+      NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
+
+  // An fade in animation should have been enqueued.
+  EXPECT_FALSE(client_.start_fade().is_null());
+  EXPECT_FALSE(client_.start_fade().IsCancelled());
+  EXPECT_EQ(kFadeDelay, client_.delay());
+
+  // Play the delay animation.
+  client_.start_fade().Run();
+  EXPECT_TRUE(client_.start_fade().IsCancelled());
+
+  scrollbar_controller_->Animate(time);
+  time += kFadeDuration;
+  scrollbar_controller_->Animate(time);
+
+  EXPECT_FALSE(scrollbar_controller_->ScrollbarsHidden());
+}
+
+// Make sure mouse down will cancel hover fade in timer, then mouse move with
+// press will not trigger hover fade in, mouse release near will trigger new
+// hover fade in.
+TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
+       MouseHoverThenMouseDownShouldCancelFadeInThenReleaseNearShouldFadeIn) {
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(1);
+
+  // Move mouse over the fade in scrollbar region of scrollbar.
+  scrollbar_controller_->DidMouseMove(
+      NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
+
+  // An fade in animation should have been enqueued.
+  EXPECT_FALSE(client_.start_fade().is_null());
+  EXPECT_FALSE(client_.start_fade().IsCancelled());
+  EXPECT_EQ(kFadeDelay, client_.delay());
+
+  // Mouse down，delay fade in should be canceled.
+  scrollbar_controller_->DidMouseDown();
+  EXPECT_TRUE(client_.start_fade().is_null() ||
+              client_.start_fade().IsCancelled());
+
+  // Move mouse hover the fade in scrollbar region of scrollbar with press.
   scrollbar_controller_->DidMouseMove(
       NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
 
+  // Should not have delay fade animation.
+  EXPECT_TRUE(client_.start_fade().is_null() ||
+              client_.start_fade().IsCancelled());
+
+  // Mouse up.
+  scrollbar_controller_->DidMouseUp();
+
   // An fade in animation should have been enqueued.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_FALSE(client_.start_fade().IsCancelled());
@@ -1210,6 +1274,45 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   EXPECT_FALSE(scrollbar_controller_->ScrollbarsHidden());
 }
 
+// Make sure mouse down will cancel hover fade in timer, then mouse move with
+// press will not trigger hover fade in, mouse release far will not trigger new
+// hover fade in.
+TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
+       MouseReleaseFarShouldNotFadeIn) {
+  base::TimeTicks time;
+  time += base::TimeDelta::FromSeconds(1);
+
+  // Move mouse over the fade in scrollbar region of scrollbar.

[bokan, 2017/06/08 20:19:54]

Nit: "fade in scrollbar region of scrollbar" should be "fade in region of
scrollbar"

+  scrollbar_controller_->DidMouseMove(
+      NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn + 1, 0));
+
+  // An fade in animation should have been enqueued.
+  EXPECT_FALSE(client_.start_fade().is_null());
+  EXPECT_FALSE(client_.start_fade().IsCancelled());
+  EXPECT_EQ(kFadeDelay, client_.delay());
+
+  // Mouse down，delay fade in should be canceled.
+  scrollbar_controller_->DidMouseDown();
+  EXPECT_TRUE(client_.start_fade().is_null() ||
+              client_.start_fade().IsCancelled());
+
+  // Move mouse far from hover the fade in scrollbar region of scrollbar with
+  // press.
+  scrollbar_controller_->DidMouseMove(
+      NearVerticalScrollbarBegin(-kMouseMoveDistanceToTriggerFadeIn, 0));
+
+  // Should not have delay fade animation.
+  EXPECT_TRUE(client_.start_fade().is_null() ||
+              client_.start_fade().IsCancelled());
+
+  // Mouse up.
+  scrollbar_controller_->DidMouseUp();
+
+  // Should not have delay fade animation.
+  EXPECT_TRUE(client_.start_fade().is_null() ||
+              client_.start_fade().IsCancelled());
+}
+
 class ScrollbarAnimationControllerAndroidTest
     : public testing::Test,
       public ScrollbarAnimationControllerClient {