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

chrome/browser/ui/views/profiles/user_manager_view.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/profiles/user_manager_view.h"
 
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/profiles/profile_metrics.h"
 #include "chrome/browser/profiles/profile_window.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_dialogs.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/user_manager.h"
 #include "chrome/browser/ui/views/auto_keep_alive.h"
 #include "chrome/grit/chromium_strings.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/controls/webview/webview.h"
 #include "ui/views/layout/fill_layout.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/window/dialog_client_view.h"
 
 #if defined(OS_WIN)
 #include "chrome/browser/shell_integration.h"
 #include "ui/base/win/shell.h"
 #include "ui/views/win/hwnd_util.h"
 #endif
 
 namespace {
 
 // Default window size.
 const int kWindowWidth = 900;
 const int kWindowHeight = 700;
 
-}
+// 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 UserManagerView* instance_ = NULL;

[Peter Kasting, 2014/09/18 18:55:05]

This shouldn't be static as it's already in an anonymous namespace.

 
-namespace chrome {
+} // namespace
 
-// Declared in browser_dialogs.h so others don't have to depend on this header.
-void ShowUserManager(const base::FilePath& profile_path_to_focus) {
-  UserManagerView::Show(
-      profile_path_to_focus, profiles::USER_MANAGER_NO_TUTORIAL);
-}
-
-void ShowUserManagerWithTutorial(profiles::UserManagerTutorialMode tutorial) {
-  UserManagerView::Show(base::FilePath(), tutorial);
-}
-
-void HideUserManager() {
-  UserManagerView::Hide();
-}
-
-}  // namespace chrome
-
-// static
-UserManagerView* UserManagerView::instance_ = NULL;
-
-UserManagerView::UserManagerView()
-    : web_view_(NULL),
-      keep_alive_(new AutoKeepAlive(NULL)) {
-}
-
-UserManagerView::~UserManagerView() {
-}
-
-// static
-void UserManagerView::Show(const base::FilePath& profile_path_to_focus,
-                           profiles::UserManagerTutorialMode tutorial_mode) {
+void UserManager::Show(

[Peter Kasting, 2014/09/18 18:55:05]

Optional: Add divider lines ("// UserManager -----------------...") above each
separate class' functions so readers see that we're implementing two different
classes here.  See e.g.
https://code.google.com/p/chromium/codesearch#chromium/src/ui/views/controls/...
as a sample of using these dividers.

+    const base::FilePath& profile_path_to_focus,
+    profiles::UserManagerTutorialMode tutorial_mode,
+    profiles::UserManagerProfileSelected profile_open_action) {
   ProfileMetrics::LogProfileSwitchUser(ProfileMetrics::OPEN_USER_MANAGER);
   if (instance_) {
     // If there's a user manager window open already, just activate it.
     instance_->GetWidget()->Activate();
     return;
   }
 
   // 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(&UserManagerView::OnGuestProfileCreated,

[Peter Kasting, 2014/09/18 18:55:05]

Somehow it seems weird to me that this is a static function instead of a member
that we'll call on the new instance we create in the next line.  I guess it
doesn't really hurt anything, though.

                  base::Passed(make_scoped_ptr(new UserManagerView)),
                  profile_path_to_focus));
 }
 
-// static
-void UserManagerView::Hide() {
+void UserManager::Hide() {
   if (instance_)
     instance_->GetWidget()->Close();
 }
 
-// static
-bool UserManagerView::IsShowing() {
+bool UserManager::IsShowing() {
   return instance_ ? instance_->GetWidget()->IsActive() : false;
 }
 
+UserManagerView::UserManagerView()
+    : web_view_(NULL),
+      keep_alive_(new AutoKeepAlive(NULL)) {
+}
+
+UserManagerView::~UserManagerView() {
+}
+
 // static
 void UserManagerView::OnGuestProfileCreated(
     scoped_ptr<UserManagerView> instance,
     const base::FilePath& profile_path_to_focus,
     Profile* guest_profile,
     const std::string& url) {
   instance_ = instance.release();  // |instance_| takes over ownership.

[Peter Kasting, 2014/09/18 18:55:05]

Should this check that |instance_| was previously null?

   instance_->Init(profile_path_to_focus, guest_profile, GURL(url));
 }
 
 void UserManagerView::Init(
     const base::FilePath& profile_path_to_focus,
     Profile* guest_profile,
     const GURL& url) {
   web_view_ = new views::WebView(guest_profile);
   web_view_->set_allow_accelerators(true);
   AddChildView(web_view_);
@@ skipping 80 matching lines @@
   // Now that the window is closed, we can allow a new one to be opened.
   // (WindowClosing comes in asynchronously from the call to Close() and we
   // may have already opened a new instance).
   if (instance_ == this)
     instance_ = NULL;
 }
 
 bool UserManagerView::UseNewStyleForThisDialog() const {
   return false;
 }