Implements the dialog view for logout button tray in public sessions.

ash/system/logout_button/logout_confirmation_dialog_view.cc

Index: ash/system/logout_button/logout_confirmation_dialog_view.cc
diff --git a/ash/system/logout_button/logout_confirmation_dialog_view.cc b/ash/system/logout_button/logout_confirmation_dialog_view.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9bd80ee72a8bfa0ff074a6e56164b10b82b9d58b
--- /dev/null
+++ b/ash/system/logout_button/logout_confirmation_dialog_view.cc
@@ -0,0 +1,167 @@
+// Copyright (c) 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 "ash/system/logout_button/logout_confirmation_dialog_view.h"
+
+#include <cmath>
+
+#include "ash/shell.h"
+#include "ash/system/logout_button/logout_button_tray.h"
+#include "ash/system/tray/system_tray_delegate.h"
+#include "ash/system/tray/tray_constants.h"
+#include "base/location.h"
+#include "grit/ash_strings.h"
+#include "ui/aura/root_window.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/l10n/time_format.h"
+#include "ui/base/ui_base_types.h"
+#include "ui/gfx/text_constants.h"
+#include "ui/views/border.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/layout/fill_layout.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+namespace internal {
+
+LogoutConfirmationDialogView::Delegate::Delegate() {
+}
+
+LogoutConfirmationDialogView::Delegate::~Delegate() {
+}
+
+void
+LogoutConfirmationDialogView::Delegate::LogoutCurrentUser() {
+  if (Shell::HasInstance())
+    Shell::GetInstance()->system_tray_delegate()->SignOut();
+}
+
+base::TimeTicks LogoutConfirmationDialogView::Delegate::GetCurrentTime() const {
+  return base::TimeTicks::Now();
+}
+
+base::TimeDelta LogoutConfirmationDialogView::Delegate::GetUpdateInterval()
+    const {
+  return base::TimeDelta::FromSeconds(1);
+}
+
+LogoutConfirmationDialogView::LogoutConfirmationDialogView(
+    LogoutButtonTray* owner, Delegate* delegate) : owner_(owner),
+                                                   delegate_(delegate) {
+  text_label_ = new views::Label;
+  text_label_->set_border(
+      views::Border::CreateEmptyBorder(0, kTrayPopupPaddingHorizontal,
+                                       0, kTrayPopupPaddingHorizontal));
+  text_label_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+  text_label_->SetMultiLine(true);
+
+  SetLayoutManager(new views::FillLayout());
+
+  AddChildView(text_label_);
+}
+
+LogoutConfirmationDialogView::~LogoutConfirmationDialogView() {
+}
+
+void LogoutConfirmationDialogView::DeleteDelegate() {
+  OnClosed();

[bartfab (slow), 2013/12/12 16:04:13]

As discussed offline, it is sufficient to just do this instead:

if (owner_)
  owner_->DeleteConfirmationDialog();

Plus, add a comment explaining that this will be triggered in tests only.

[binjin, 2013/12/17 10:29:49]

Done.

+  delete this;
+}
+
+bool LogoutConfirmationDialogView::Accept() {
+  LogoutCurrentUser();
+  return true;
+}
+
+ui::ModalType LogoutConfirmationDialogView::GetModalType() const {
+  return ui::MODAL_TYPE_SYSTEM;
+}
+
+string16 LogoutConfirmationDialogView::GetWindowTitle() const {
+  return l10n_util::GetStringUTF16(IDS_ASH_LOGOUT_CONFIRMATION_TITLE);
+}
+
+string16 LogoutConfirmationDialogView::GetDialogButtonLabel(
+    ui::DialogButton button) const {
+  if (button == ui::DIALOG_BUTTON_OK)
+    return l10n_util::GetStringUTF16(IDS_ASH_LOGOUT_CONFIRMATION_BUTTON);
+  return views::DialogDelegateView::GetDialogButtonLabel(button);
+}
+
+void LogoutConfirmationDialogView::OnClosed() {
+  if (owner_) {

[bartfab (slow), 2013/12/12 16:04:13]

How can the owner_ ever be NULL?

[binjin, 2013/12/17 10:29:49]

I'm not sure the reason, but OnClosed() is actually called twice during session
logout. And I believe the times OnClosed() is called is kind of undefined, so I
added this condition check. 

[bartfab (slow), 2013/12/17 13:21:03]

This is a bit worrying. It would seem that OnClosed() should be called exactly
once, when the dialog is getting closed. Could you quickly check in a debugger
or print out a stack trace whenever OnClosed() is called to see why it gets
called twice during logout (Philipp always remembers by heart how to print a
stack trace, you can check with him for the right code snippet)?

[binjin, 2013/12/17 14:58:08]

I checked the stack trace for both calls. here is the different part:

 [0x7fe15aeef893] ash::internal::LogoutConfirmationDialogView::OnClosed()
 [0x7fe158c69060] views::DialogClientView::CanClose()
 [0x7fe158c6ca19] views::NonClientView::CanClose()
 [0x7fe158c5d8f7] views::Widget::Close()
 [0x7fe15aeefb3f]
ash::internal::LogoutConfirmationDialogView::LogoutCurrentUser()
 [0x7fe15aeef7de] ash::internal::LogoutConfirmationDialogView::Accept()
 [0x7fe158c6ab86] views::DialogDelegate::Accept()
 [0x7fe158c68c63] views::DialogClientView::AcceptWindow()
 [0x7fe158c6a00a] views::DialogClientView::ButtonPressed()
vs. 
 [0x7fe15aeef893] ash::internal::LogoutConfirmationDialogView::OnClosed()
 [0x7fe158c6a8b4] views::DialogClientView::Close()
 [0x7fe158c68c8e] views::DialogClientView::AcceptWindow()
 [0x7fe158c6a00a] views::DialogClientView::ButtonPressed()

So it turns out it's unnecessary to close the dialog in
LogoutConfirmationDialogView::LogoutCurrentUser() for real browser environment
after user clicked Yes button and Accept() was called, but it's necessary for
tests with my current approach. I think it's okay and I prefer to just left
everything unchanged here.

[bartfab (slow), 2013/12/17 15:57:46]

I think allowing OnClosed() to be called twice is setting up a dangerous
situation that someone later may run into - it is unexpected behavior that your
code handles but future code may not deal with properly. It would be best to
change it so that OnClosed() is only called once in the production code path. If
this means that OnClosed() is never called in testing code when a click on "OK"
is simulated, that's actually OK: The core functionality we want to test is that
when the user clicks "OK," a logout is initiated. Whether the dialog gets closed
or not does not really matter. Once the delegate has been reset, the dialog does
nothing anyway. And even if it persists on the screen for a split second longer,
it will be torn down together with the browser in a moment as the logout
proceeds.

[binjin, 2013/12/18 18:13:14]

Done.

+    owner_->DeleteConfirmationDialog();
+    owner_ = NULL;
+    timer_.Stop();
+    // nullify the delegate to prevent future activities of the dialog.

[bartfab (slow), 2013/12/12 16:04:13]

Nit: s/nullify/Nullify/

[binjin, 2013/12/17 10:29:49]

Done.

+    delegate_ = NULL;
+  }
+}
+
+void LogoutConfirmationDialogView::Show(base::TimeDelta duration) {
+  if (!delegate_)
+    return;
+  countdown_start_time_ = delegate_->GetCurrentTime();
+  duration_ = duration;
+
+  UpdateCountdown();
+
+  // For testing purpose, only actually display the dialog if an existing
+  // ash::Shell is available.
+  if (ash::Shell::HasInstance()) {
+    views::DialogDelegate::CreateDialogWidget(
+        this, ash::Shell::GetPrimaryRootWindow(), NULL);
+    GetWidget()->Show();
+  }
+
+  timer_.Start(FROM_HERE,
+               delegate_->GetUpdateInterval(),
+               this,
+               &LogoutConfirmationDialogView::UpdateCountdown);
+}
+
+void LogoutConfirmationDialogView::UpdateDialogDuration(
+    base::TimeDelta duration) {
+  duration_ = duration;
+  UpdateCountdown();
+}
+
+void LogoutConfirmationDialogView::LogoutCurrentUser() {
+  if (!delegate_)
+    return;
+  // Backup the delegate, since closing widget will nullify it.
+  Delegate* delegate = delegate_;
+  // For testing purpose.
+  if (GetWidget()) {
+    GetWidget()->Close();
+    delegate->LogoutCurrentUser();

[bartfab (slow), 2013/12/12 16:04:13]

Why did you choose this ordering? If you called LogoutCurrentUser() first, you
would not need to store the |delegate_| in a temporary.

[binjin, 2013/12/17 10:29:49]

I choose this ordering because I think the session logout might be complicated
and kind of undefined in real browser environment, so I want to make sure the
dialog is closed properly before actually try to log out the session. And I
think a temporary pointer with comments didn't make the code much more
complicated and hard to follow.

+  } else {
+    delegate->LogoutCurrentUser();
+    DeleteDelegate();

[bartfab (slow), 2013/12/12 16:04:13]

Could you call Close() here instead?

[binjin, 2013/12/17 10:29:49]

I think the default implementation of DialogDelegate::Close() didn't actually do
clean up work, and in tests that's the only necessary task.

+  }
+}
+
+void LogoutConfirmationDialogView::UpdateCountdown() {
+  if (!delegate_)
+    return;
+  const base::TimeDelta time_remaining = countdown_start_time_
+      + duration_ - delegate_->GetCurrentTime();

[bartfab (slow), 2013/12/12 16:04:13]

Nit: The style guide says the + should go on the previous line.

[binjin, 2013/12/17 10:29:49]

Done.

+  // Round the remaining time to nearest second, and use this value for
+  // the countdown display and actual enforcement.
+  int seconds_remaining = round(time_remaining.InSecondsF());
+  if (seconds_remaining > 0) {
+    text_label_->SetText(l10n_util::GetStringFUTF16(
+        IDS_ASH_LOGOUT_CONFIRMATION_WARNING,
+        ui::TimeFormat::TimeDurationLong(base::TimeDelta::FromSeconds(
+            seconds_remaining))));
+  } else {
+    text_label_->SetText(l10n_util::GetStringUTF16(
+        IDS_ASH_LOGOUT_CONFIRMATION_WARNING_NOW));
+    timer_.Stop();
+    LogoutCurrentUser();

[bartfab (slow), 2013/12/12 16:04:13]

At this point, the dialog is still open and the delegate_ is non-NULL. Could the
user click one of the buttons, causing unexpected behavior?

[binjin, 2013/12/17 10:29:49]

The LogoutCurrentUser() here is LogoutConfirmationDialogView::LogoutCurrentUser,
instead of the LogoutCurrentUser() from Delegate. The |delegate_| is nullified
and dialog is closed here.

+  }
+}
+
+}  // namespace internal
+}  // namespace ash