Reset need_trigger_scrollbar_show_ in SAC::DidMouseLeave

cc/input/scrollbar_animation_controller.cc

Index: cc/input/scrollbar_animation_controller.cc
diff --git a/cc/input/scrollbar_animation_controller.cc b/cc/input/scrollbar_animation_controller.cc
index 52f83e53ecae5db058a52ee1d4f2de8b6d64eddf..0d4e00a1389942645474053325b459b24c9b5a13 100644
--- a/cc/input/scrollbar_animation_controller.cc
+++ b/cc/input/scrollbar_animation_controller.cc
@@ -243,6 +243,7 @@ void ScrollbarAnimationController::DidMouseLeave() {
   horizontal_controller_->DidMouseLeave();
 
   delayed_scrollbar_show_.Cancel();
+  need_trigger_scrollbar_show_ = false;
 
   if (ScrollbarsHidden() || Captured())
     return;