Switching to the correct desktop when a system modal dialog gets shown

chrome/browser/ui/ash/multi_user/multi_user_window_manager_chromeos.cc

 // Copyright 2013 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/ash/multi_user/multi_user_window_manager_chromeos.h"
 
 #include "apps/shell_window.h"
 #include "apps/shell_window_registry.h"
 #include "ash/ash_switches.h"
 #include "ash/multi_profile_uma.h"
+#include "ash/root_window_controller.h"
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
+#include "ash/shell_window_ids.h"
 #include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/window_positioner.h"
 #include "ash/wm/window_state.h"
 #include "base/auto_reset.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 436 matching lines @@
     return;
   SetWindowOwner(browser->window()->GetNativeWindow(),
                  multi_user_util::GetUserIDFromProfile(browser->profile()));
 }
 
 void MultiUserWindowManagerChromeOS::SetWindowVisibility(
     aura::Window* window, bool visible) {
   if (window->IsVisible() == visible)
     return;
 
+  // Hiding a system modal dialog should not be allowed. Instead we switch to
+  // the user which is showing the system modal window.
+  if (!visible) {
+    // Get the system modal container for the window's root window.
+    ash::internal::RootWindowController* controller =

[sky, 2013/11/16 00:34:55]

Classes in internal namespaces shouldn't be used outside of the directory. So,
either RWC shouldn't be in internal or you shouldn't be using RWC. You should be
able to use GetChildById on the root.

[Mr4D (OOO till 08-26), 2013/11/16 00:54:27]

Done.

+        ash::internal::GetRootWindowController(window->GetRootWindow());
+    aura::Window* system_modal_container =
+        controller->GetContainer(
+            ash::internal::kShellWindowId_SystemModalContainer);
+    if (window->parent() == system_modal_container) {
+      // The window is system modal and we need to find the parent which owns
+      // it so that we can switch to the desktop accordingly.
+      std::string user_id = GetUserPresentingWindow(window);
+      if (user_id.empty()) {
+        aura::Window* owning_window = GetOwningWindowInTransientChain(window);
+        if (owning_window)

[sky, 2013/11/16 00:34:55]

Should this be a DCHECK? Otherwise you know 490 is going to hit?

I don't know your code enough to say if DCHECK is right here or not. Its very
likely that a system model dialog has no owner.

[Mr4D (OOO till 08-26), 2013/11/16 00:54:27]

Done.

+          user_id = GetUserPresentingWindow(owning_window);
+      }
+      DCHECK(!user_id.empty());
+      ash::Shell::GetInstance()->session_state_delegate()->SwitchActiveUser(
+          user_id);
+      return;
+    }
+  }
+
   // To avoid that these commands are recorded as any other commands, we are
   // suppressing any window entry changes while this is going on.
   base::AutoReset<bool> suppressor(&suppress_visibility_changes_, true);
 
   if (visible) {
     ShowWithTransientChildrenRecursive(window);
   } else {
     if (window->HasFocus())
       window->Blur();
     window->Hide();
@@ skipping 78 matching lines @@
     // To prevent these commands from being recorded as any other commands, we
     // are suppressing any window entry changes while this is going on.
     // Instead of calling SetWindowVisible, only show gets called here since all
     // dependents have been shown previously already.
     base::AutoReset<bool> suppressor(&suppress_visibility_changes_, true);
     window->Show();
   }
 }
 
 }  // namespace chrome