Reset need_trigger_scrollbar_show_ in SAC::DidMouseLeave

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 1026 matching lines @@
   // Move mouse out of scrollbar，delay show should be canceled.
   scrollbar_controller_->DidMouseMoveNear(
       VERTICAL, kMouseMoveDistanceToTriggerShow - kThumbThickness);
   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,
-       MouseHoverThenLeaveShouldCancelShow) {
+       MouseHoverThenLeaveShouldCancelShowThenEnterShouldShow) {
   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 window，delay show should be canceled.
   scrollbar_controller_->DidMouseLeave();
   EXPECT_TRUE(client_.start_fade().is_null() ||
               client_.start_fade().IsCancelled());
+
+  // 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());
+
+  // Play the delay animation.
+  client_.start_fade().Run();
+  EXPECT_TRUE(client_.start_fade().IsCancelled());
+  EXPECT_FALSE(scrollbar_controller_->ScrollbarsHidden());
 }
 
 class ScrollbarAnimationControllerAndroidTest
     : public testing::Test,
       public ScrollbarAnimationControllerClient {
  public:
   ScrollbarAnimationControllerAndroidTest()
       : host_impl_(&task_runner_provider_, &task_graph_runner_),
         did_request_redraw_(false),
         did_request_animate_(false) {}
@@ skipping 467 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