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

chrome/browser/background/background_mode_manager.h

Index: chrome/browser/background/background_mode_manager.h
diff --git a/chrome/browser/background/background_mode_manager.h b/chrome/browser/background/background_mode_manager.h
index d4f9008b5e431625a620df7593304ff90f1f2187..538ea52b49089763d1491916a7ffa10fabc57a54 100644
--- a/chrome/browser/background/background_mode_manager.h
+++ b/chrome/browser/background/background_mode_manager.h
@@ -306,6 +306,11 @@ class BackgroundModeManager
   // Returns true if we should be in background mode.
   bool ShouldBeInBackgroundMode() const;
 
+  // Finds the BackgroundModeData associated with the last active profile,
+  // if the profile isn't locked. Returns NULL otherwise.
+  BackgroundModeManager::BackgroundModeData*
+      GetBackgroundModeDataForLastProfile() const;
+
   // Reference to the profile info cache. It is used to update the background
   // app status of profiles when they open/close background apps.
   ProfileInfoCache* profile_cache_;