Multiprofile security: Show a warning messagebox when desktop casting/sharing is turned on upon user

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 9bd30a016436bd6ba49874f137e2528f86410131..cbd5f13bd2c02bb3e4db8b16ff951de99264e3b7 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -182,8 +182,10 @@ void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
   AddTrayItem(new TraySms(this));
   AddTrayItem(new TrayBluetooth(this));
   AddTrayItem(new TrayDisplay(this));
-  AddTrayItem(new ScreenCaptureTrayItem(this));
-  AddTrayItem(new ScreenShareTrayItem(this));
+  screen_capture_tray_item_ = new ScreenCaptureTrayItem(this);
+  AddTrayItem(screen_capture_tray_item_);
+  screen_share_tray_item_ = new ScreenShareTrayItem(this);
+  AddTrayItem(screen_share_tray_item_);
   AddTrayItem(new MultiProfileMediaTrayItem(this));
   AddTrayItem(new TrayAudioChromeOs(this));
   AddTrayItem(new TrayBrightness(this));