Add LogoutConfirmationController to show LogoutConfirmationDialogs

ash/system/logout_confirmation/logout_confirmation_controller.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 "ash/system/logout_confirmation/logout_confirmation_controller.h"
+
+#include "ash/session_state_delegate.h"
+#include "ash/shell.h"
+#include "ash/system/logout_confirmation/logout_confirmation_dialog.h"
+#include "base/location.h"
+#include "base/time/default_tick_clock.h"
+#include "base/time/tick_clock.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+namespace internal {
+
+LogoutConfirmationController::LogoutConfirmationController(
+    const base::Closure& logout_closure)
+    : clock_(reinterpret_cast<base::TickClock*>(new base::DefaultTickClock)),
+      logout_closure_(logout_closure),
+      dialog_(NULL),
+      logout_timer_(false, false) {
+  if (Shell::HasInstance())
+    Shell::GetInstance()->AddShellObserver(this);
+}
+
+LogoutConfirmationController::~LogoutConfirmationController() {
+  if (Shell::HasInstance())
+    Shell::GetInstance()->RemoveShellObserver(this);

[stevenjb, 2014/03/04 23:33:30]

I think we need to destroy dialog_ here (if not NULL), or at least clear its
pointer to us. Otherwise, since LogoutConfirmationDialog is owned by the Views
hierarchy, which gets destroyed *after* LogoutConfirtmationController, it could
access this class after it is destroyed (e.g. if Logout were clicked as Chrome
is shutting down).

[bartfab (slow), 2014/03/05 18:19:46]

I think the code was actually safe: In my understanding, the loops are no longer
spun at this point in the shutdown sequence, so input and timer events should no
longer be generated or processed. But I agree that closing the dialog is even
safer. Done.

+}
+
+void LogoutConfirmationController::ConfirmLogout(
+    base::TimeTicks logout_time) {
+  if (!logout_time_.is_null() && logout_time >= logout_time_) {
+    // If a confirmation dialog is already being shown and its countdown expires
+    // no later than the |logout_time| requested now, keep the current dialog
+    // open.
+    return;
+  }
+  logout_time_ = logout_time;
+
+  if (!dialog_) {
+    // Show confirmation dialog unless this is a unit test without a Shell.
+    if (Shell::HasInstance())
+      dialog_ = new LogoutConfirmationDialog(this, logout_time_);
+  } else {
+    dialog_->Update(logout_time_);
+  }
+
+  logout_timer_.Start(FROM_HERE,
+                      logout_time_ - clock_->NowTicks(),
+                      logout_closure_);
+}
+
+void LogoutConfirmationController::SetClockForTesting(
+    scoped_ptr<base::TickClock> clock) {
+  clock_ = clock.Pass();
+}
+
+void LogoutConfirmationController::OnLockStateChanged(bool locked) {
+  if (!locked || logout_time_.is_null())
+    return;
+
+  // If the screen is locked while a confirmation dialog is being shown, close
+  // the dialog.
+  logout_time_ = base::TimeTicks();
+  if (dialog_)
+    dialog_->GetWidget()->Close();
+  logout_timer_.Stop();
+}
+
+void LogoutConfirmationController::OnLogoutConfirmed() {
+  logout_timer_.Stop();
+  logout_closure_.Run();
+}
+
+void LogoutConfirmationController::OnDialogClosed() {
+  logout_time_ = base::TimeTicks();
+  dialog_ = NULL;
+  logout_timer_.Stop();
+}
+
+}  // namespace internal
+}  // namespace ash