Fix Chrome crashes on calling OnTrayVisibilityChange

ash/common/system/status_area_widget.cc

Index: ash/common/system/status_area_widget.cc
diff --git a/ash/common/system/status_area_widget.cc b/ash/common/system/status_area_widget.cc
index 06bdf90c0d2c21eceda997e746f013cf09ae213d..e43bdc08f6c609413250f20639f1dbea7cbbb916 100644
--- a/ash/common/system/status_area_widget.cc
+++ b/ash/common/system/status_area_widget.cc
@@ -282,6 +282,9 @@ void StatusAreaWidget::AddImeMenuTray() {
 
 bool StatusAreaWidget::IsNextVisibleTrayToLogout(
     TrayBackgroundView* tray) const {
+  if (!logout_button_tray_) {

[sadrul, 2016/12/13 17:06:58]

Don't need {}

+    return false;
+  }
   int logout_button_index =
       status_area_widget_delegate_->GetIndexOf(logout_button_tray_);
   // Logout button should always exist.