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

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

Index: chrome/browser/ui/cocoa/profiles/user_manager_mac.mm
diff --git a/chrome/browser/ui/cocoa/profiles/user_manager_mac.mm b/chrome/browser/ui/cocoa/profiles/user_manager_mac.mm
index 957d95ba57bb6b8b04cab3e077f8fa47836a668c..faf3223da30bedc7ad98b4e96b36b57db56ab26b 100644
--- a/chrome/browser/ui/cocoa/profiles/user_manager_mac.mm
+++ b/chrome/browser/ui/cocoa/profiles/user_manager_mac.mm
@@ -10,6 +10,7 @@
 #include "chrome/browser/ui/browser_dialogs.h"
 #import "chrome/browser/ui/cocoa/browser_window_utils.h"
 #include "chrome/browser/ui/cocoa/chrome_event_processing_window.h"
+#include "chrome/browser/ui/user_manager.h"
 #include "chrome/grit/chromium_strings.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/browser/web_contents.h"
@@ -23,23 +24,37 @@
 const int kWindowWidth = 900;
 const int kWindowHeight = 700;
 
-namespace chrome {
+// An open User Manager window. There can only be one open at a time. This
+// is reset to NULL when the window is closed.
+static UserManagerMac* instance_ = NULL;  // Weak.
 
-// Declared in browser_dialogs.h so others don't have to depend on this header.
-void ShowUserManager(const base::FilePath& profile_path_to_focus) {
-  UserManagerMac::Show(
-      profile_path_to_focus, profiles::USER_MANAGER_NO_TUTORIAL);
-}
+void UserManager::Show(
+    const base::FilePath& profile_path_to_focus,
+    profiles::UserManagerTutorialMode tutorial_mode,
+    profiles::UserManagerProfileSelected profile_open_action) {
+  if (instance_) {
+    // If there's a user manager window open already, just activate it.
+    [instance_->window_controller_ show];
+    return;
+  }
 
-void ShowUserManagerWithTutorial(profiles::UserManagerTutorialMode tutorial) {
-  UserManagerMac::Show(base::FilePath(), tutorial);
+  // Create the guest profile, if necessary, and open the User Manager
+  // from the guest profile.
+  profiles::CreateGuestProfileForUserManager(
+      profile_path_to_focus,
+      tutorial_mode,
+      profile_open_action,
+      base::Bind(&UserManagerMac::OnGuestProfileCreated));
 }
 
-void HideUserManager() {
-  UserManagerMac::Hide();
+void UserManager::Hide() {
+  if (instance_)
+    [instance_->window_controller_ close];
 }
 
-}  // namespace chrome
+bool UserManager::IsShowing() {
+  return instance_ ? [instance_->window_controller_ isVisible]: false;
+}
 
 // Custom WebContentsDelegate that allows handling of hotkeys.
 class UserManagerWebContentsDelegate : public content::WebContentsDelegate {
@@ -175,34 +190,6 @@ UserManagerMac::~UserManagerMac() {
 }
 
 // static
-void UserManagerMac::Show(const base::FilePath& profile_path_to_focus,
-                          profiles::UserManagerTutorialMode tutorial_mode) {
-  if (instance_) {
-    // If there's a user manager window open already, just activate it.
-    [instance_->window_controller_ show];
-    return;
-  }
-
-  // Create the guest profile, if necessary, and open the User Manager
-  // from the guest profile.
-  profiles::CreateGuestProfileForUserManager(
-      profile_path_to_focus,
-      tutorial_mode,
-      base::Bind(&UserManagerMac::OnGuestProfileCreated));
-}
-
-// static
-void UserManagerMac::Hide() {
-  if (instance_)
-    [instance_->window_controller_ close];
-}
-
-// static
-bool UserManagerMac::IsShowing() {
-  return instance_ ? [instance_->window_controller_ isVisible]: false;
-}
-
-// static
 void UserManagerMac::OnGuestProfileCreated(Profile* guest_profile,
                                            const std::string& url) {
   instance_ = new UserManagerMac(guest_profile);