Removes caching of whether the launcher should be visible from

ash/system/tray/tray_background_view.cc

Index: ash/system/tray/tray_background_view.cc
diff --git a/ash/system/tray/tray_background_view.cc b/ash/system/tray/tray_background_view.cc
index 98cd651efd816206a3572d150bac81f2e3f604fc..147c70f55625b17b4bc8e827931fbf8657f14201 100644
--- a/ash/system/tray/tray_background_view.cc
+++ b/ash/system/tray/tray_background_view.cc
@@ -190,13 +190,11 @@ void TrayBackgroundView::Initialize() {
 void TrayBackgroundView::OnMouseEntered(const ui::MouseEvent& event) {
   hover_background_animator_.SetPaintsBackground(true,
       internal::BackgroundAnimator::CHANGE_ANIMATE);
-  UpdateShouldShowLauncher();
 }
 
 void TrayBackgroundView::OnMouseExited(const ui::MouseEvent& event) {
   hover_background_animator_.SetPaintsBackground(false,
       internal::BackgroundAnimator::CHANGE_ANIMATE);
-  UpdateShouldShowLauncher();
 }
 
 void TrayBackgroundView::ChildPreferredSizeChanged(views::View* child) {
@@ -279,9 +277,5 @@ void TrayBackgroundView::SetBorder() {
   }
 }
 
-void TrayBackgroundView::UpdateShouldShowLauncher() {
-  status_area_widget()->UpdateShouldShowLauncher();
-}
-
 }  // namespace internal
 }  // namespace ash