Access to Chrome via the System Tray should go through the User Manager.

chrome/browser/ui/cocoa/profiles/user_manager_mac.h

Index: chrome/browser/ui/cocoa/profiles/user_manager_mac.h
diff --git a/chrome/browser/ui/cocoa/profiles/user_manager_mac.h b/chrome/browser/ui/cocoa/profiles/user_manager_mac.h
index e71006271f43fc891082233ea50589b5dccc426d..8679d87805bac54f12d60ca0a8b07922906b378d 100644
--- a/chrome/browser/ui/cocoa/profiles/user_manager_mac.h
+++ b/chrome/browser/ui/cocoa/profiles/user_manager_mac.h
@@ -25,9 +25,11 @@ class UserManagerMac {
   // Shows the User Manager or re-activates an existing one, focusing the
   // profile given by |profile_path_to_focus|. Based on the value of
   // |tutorial_mode|, a tutorial could be shown, in which case
-  // |profile_path_to_focus| is ignored.
+  // |profile_path_to_focus| is ignored. After a profile is opened, execute the
+  // |profile_open_action|.
   static void Show(const base::FilePath& profile_path_to_focus,
-                   profiles::UserManagerTutorialMode tutorial_mode);
+                   profiles::UserManagerTutorialMode tutorial_mode,
+                   profiles::UserManagerProfileSelected profile_open_action);
 
   // Hide the User Manager.
   static void Hide();