Change the distance trigger scrollbar show

cc/input/scrollbar_animation_controller_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.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"
@@ skipping 1015 matching lines @@
 }
 
 // Scrollbars should not schedule a new delay show when the mouse hovers inside
 // a scrollbar already scheduled a delay show.
 TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
        MouseHoverScrollbarAndMoveInside) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Move mouse over scrollbar.
   scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);

[bokan, 2017/04/10 14:30:17]

This should be kMouseMoveDistanceToTriggerShow - 1. in order to catch this bug.

 
   // 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());
 
   base::Closure& fade = client_.start_fade();
   // Move mouse inside scrollbar. should not post a new show.
-  scrollbar_controller_->DidMouseMoveNear(
-      VERTICAL, kMouseMoveDistanceToTriggerShow - kThumbThickness - 1);
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow - 1);
 
   EXPECT_TRUE(fade.Equals(client_.start_fade()));
 }
 
 // Scrollbars should cancel delay show when mouse hover hidden scrollbar then
 // move out of scrollbar.
 TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
        MouseHoverThenOutShouldCancelShow) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
 
   // Move mouse over scrollbar.
   scrollbar_controller_->DidMouseMoveNear(VERTICAL, 0);
 
   // 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);
+  scrollbar_controller_->DidMouseMoveNear(VERTICAL,
+                                          kMouseMoveDistanceToTriggerShow);
   EXPECT_TRUE(client_.start_fade().is_null() ||
               client_.start_fade().IsCancelled());
 }
 
 // Scrollbars should cancel delay show when mouse hover hidden scrollbar then
 // move out of window.
 TEST_F(ScrollbarAnimationControllerAuraOverlayTest,
        MouseHoverThenLeaveShouldCancelShowThenEnterShouldShow) {
   base::TimeTicks time;
   time += base::TimeDelta::FromSeconds(1);
@@ skipping 508 matching lines @@
   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