mash: Close system tray bubble on click outside its bounds, part 1

ash/system/tray/system_tray.cc

Index: ash/system/tray/system_tray.cc
diff --git a/ash/system/tray/system_tray.cc b/ash/system/tray/system_tray.cc
index 211570870c7057dd021b1e584d8692b7a91c53c7..e48cd1feb5f3c207a3ebf975db1aecf2f4789edf 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -500,6 +500,8 @@ void SystemTray::ShowItems(const std::vector<SystemTrayItem*>& items,
                                            menu_width,
                                            kTrayPopupMaxWidth);
     init_params.can_activate = can_activate;
+    // Mus cannot use EventHandlers to close the tray, so it uses capture.
+    init_params.close_via_capture = Shell::GetInstance()->in_mus();
     init_params.first_item_has_no_margin = true;
     if (detailed) {
       // This is the case where a volume control or brightness control bubble
@@ -572,6 +574,8 @@ void SystemTray::UpdateNotificationBubble() {
                                          GetAnchorAlignment(),
                                          kTrayPopupMinWidth,
                                          kTrayPopupMaxWidth);
+  // Mus cannot use EventHandlers to close the tray, so it uses capture.
+  init_params.close_via_capture = Shell::GetInstance()->in_mus();
   init_params.first_item_has_no_margin = true;
   init_params.arrow_color = kBackgroundColor;
   init_params.arrow_offset = GetTrayXOffset(notification_items_[0]);