Change the distance trigger scrollbar show

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 c4fda1a43c8331c22fcf7fe807f678215b20f1ef..587a48b2cc1c6ec15005c5771d80f0ba0ba915fc 100644
--- a/cc/input/scrollbar_animation_controller_unittest.cc
+++ b/cc/input/scrollbar_animation_controller_unittest.cc
@@ -1006,13 +1006,14 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest, MouseLeaveFadeOut) {
   EXPECT_EQ(kFadeOutDelay, client_.delay());
 }
 
-// Scrollbars should schedule a delay show when mouse hover hidden scrollbar.
+// Scrollbars should schedule a delay show when mouse near a hidden scrollbar.
 TEST_F(ScrollbarAnimationControllerAuraOverlayTest, BasicMouseHoverShow) {

[chaopeng, 2017/04/10 14:56:11]

Here we are not hover anymore. what should we name this test.

[bokan, 2017/04/10 18:14:16]

We are hovering over the "show scrollbar region" rather than the scrollbar. I
think it's fine but if you want to change to something more descriptive that's
fine too.

   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);
+  // Move mouse near scrollbar within kMouseMoveDistanceToTriggerShow.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 1);
 
   // An show animation should have been enqueued.
   EXPECT_FALSE(client_.start_fade().is_null());
@@ -1032,8 +1033,9 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);
+  // Move mouse near scrollbar within kMouseMoveDistanceToTriggerShow.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 1);
 
   // An show animation should have been enqueued.
   EXPECT_FALSE(client_.start_fade().is_null());
@@ -1041,31 +1043,33 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   EXPECT_EQ(kShowDelay, client_.delay());
 
   base::Closure& fade = client_.start_fade();
-  // Move mouse inside scrollbar. should not post a new show.
-  scrollbar_controller_->DidMouseMoveNear(
-      VERTICAL, kMouseMoveDistanceToTriggerShow - kThumbThickness - 1);
+  // Move mouse near scrollbar still within kMouseMoveDistanceToTriggerShow.
+  // should not post a new show.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 2);
 
   EXPECT_TRUE(fade.Equals(client_.start_fade()));
 }
 
-// Scrollbars should cancel delay show when mouse hover hidden scrollbar then
-// move out of scrollbar.
+// Scrollbars should cancel delay show when mouse near hidden scrollbar then
+// move far away.
 TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
        MouseHoverThenOutShouldCancelShow) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);
+  // Move mouse near scrollbar within kMouseMoveDistanceToTriggerShow.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 1);
 
   // An show animation should have been enqueued.
   EXPECT_FALSE(client_.start_fade().is_null());
   EXPECT_FALSE(client_.start_fade().IsCancelled());
   EXPECT_EQ(kShowDelay, client_.delay());
 
-  // Move mouse out of scrollbar，delay show should be canceled.
-  scrollbar_controller_->DidMouseMoveNear(
-      VERTICAL, kMouseMoveDistanceToTriggerShow - kThumbThickness);
+  // Move mouse far away，delay show should be canceled.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow);
   EXPECT_TRUE(client_.start_fade().is_null() ||
               client_.start_fade().IsCancelled());
 }
@@ -1077,8 +1081,9 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
-  // Move mouse over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);
+  // Move mouse near scrollbar within kMouseMoveDistanceToTriggerShow.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 1);
 
   // An show animation should have been enqueued.
   EXPECT_FALSE(client_.start_fade().is_null());
@@ -1090,8 +1095,9 @@ TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
   EXPECT_TRUE(client_.start_fade().is_null() ||
               client_.start_fade().IsCancelled());
 
-  // Move mouse over scrollbar.
-  scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);
+  // Move mouse near scrollbar within kMouseMoveDistanceToTriggerShow.
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 1);
 
   // An show animation should have been enqueued.
   EXPECT_FALSE(client_.start_fade().is_null());