Add LogoutConfirmationController to show LogoutConfirmationDialogs

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index c70e584ccb1fe530cf363e4a08de49c36bb75ff8..055b809b70472b823cb98a18ba4fe3f188652072 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -49,6 +49,7 @@
 #include "ash/shell_factory.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/locale/locale_notification_controller.h"
+#include "ash/system/logout_confirmation/logout_confirmation_controller.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/system_tray_notifier.h"
@@ -80,8 +81,10 @@
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace_controller.h"
 #include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
+#include "base/time/default_tick_clock.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/user_action_client.h"
 #include "ui/aura/env.h"
@@ -655,6 +658,9 @@ Shell::~Shell() {
   // TODO(xiyuan): Move it back when app list container is no longer needed.
   app_list_controller_.reset();
 
+  // Destroy the LogoutConfirmationController before the SystemTrayDelegate.
+  logout_confirmation_controller_.reset();
+
   // Destroy SystemTrayDelegate before destroying the status area(s).
   system_tray_delegate_->Shutdown();
   system_tray_delegate_.reset();
@@ -952,6 +958,13 @@ void Shell::Init() {
   // Initialize system_tray_delegate_ after StatusAreaWidget is created.
   system_tray_delegate_->Initialize();
 
+  // Create the LogoutConfirmationController after the SystemTrayDelegate.
+  logout_confirmation_controller_.reset(
+      new internal::LogoutConfirmationController(
+          scoped_ptr<base::TickClock>(new base::DefaultTickClock),

[stevenjb, 2014/02/27 17:58:44]

nit: use make_scoped_ptr?

[bartfab (slow), 2014/02/28 12:13:49]

make_scoped_ptr cannot be used when upcasting, as done here from a
DefaultTickClock to a TickClock.

[stevenjb, 2014/03/04 23:33:29]

Ah, I missed the upcast. I like this version better without the need for a cast.

+          base::Bind(&SystemTrayDelegate::SignOut,
+                     base::Unretained(system_tray_delegate_.get()))));

[stevenjb, 2014/02/27 17:58:44]

Even though we are explicitly creating/destroying LogoutConfirmationController
after/before SystemTrayDelegate, it might be more clear/robust/maintainable to
use a local function that calls ash::Shell::GetInstance(), checks
shell->system_tray_delegate(), and calls
shell->system_tray_delegate()->SignOut(). That way even if the callback somehow
outlives LogoutConfirmationController, or code gets moved around, the callback
will still be safe.

[bartfab (slow), 2014/02/28 12:13:49]

The reason for doing it this way is that I can supply a different closure for
tests. It is essentially a delegate interface. SystemTrayDelegate::SignOut() is
one possible delegate. Tests will use another delegate that records that the
method has been called only.

[stevenjb, 2014/03/04 23:33:29]

Testability is important, but stability even more so. It looks like this would
be safe since logout_confirmation_controller_ is destroyed before
system_tray_delegate_, but that's only true so long as
LogoutConfirtmationController never passes along the callback. We might want to
at least make a comment to that effect.

Meanwhile, in convincing myself of that I think we may have a different edge
case, I'll comment that part of the code separately.

[bartfab (slow), 2014/03/05 18:19:44]

Added a comment.

+
   // TODO(oshima): Initialize all RootWindowControllers once, and
   // initialize controller/delegates above when initializing the
   // primary root window controller.