Remote assistance on Chrome OS Part V - It2MeHost Continue Window

This CL implements the ContinueWindow on ChromeOS, which will
be shown to the user for confirmation after 10 minutes into a Remote
Assistance session.

To implement the ContinueWindow, this CL introduces a new class
MessageBox, which is a re-usable component built on top of the
widget framework.

BUG=424908

Committed: https://crrev.com/6410d7ad4937a4a86e9ad28b9ecf99f961305b2d
Cr-Commit-Position: refs/heads/master@{#302657}

Review URL: https://codereview.chromium.org/690183002

Cr-Commit-Position: refs/heads/master@{#302706}

remoting/host/chromeos/message_box.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 "remoting/host/chromeos/message_box.h"
+
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/views/controls/message_box_view.h"
+#include "ui/views/widget/widget.h"
+#include "ui/views/window/dialog_delegate.h"
+
+namespace remoting {
+
+// MessageBox::Core creates the dialog using the views::DialogWidget.  The
+// DialogWidget is created by the caller but its lifetime is managed by the
+// NativeWidget.  The DialogWidget communicates with the caller using the
+//.DialogDelegateView interface, which must remain valid until DeleteDelegate()
+// is called, at which the DialogDelegateView deletes itself.
+//
+// The Core class is introduced to abstract this awkward ownership model.  The
+// Core and the MessageBox hold a raw references to each other, which is
+// invalidated when either side are destroyed.
+class MessageBox::Core : public views::DialogDelegateView {
+ public:
+  Core(const base::string16& title_label,
+       const base::string16& message_label,
+       const base::string16& ok_label,
+       const base::string16& cancel_label,
+       ResultCallback result_callback,
+       MessageBox* message_box);
+
+  // Mirrors the public MessageBox interface.
+  void Show();
+  void Hide();
+
+  // views::DialogDelegateView interface.
+  bool Accept() override;
+  bool Cancel() override;
+  ui::ModalType GetModalType() const override;
+  base::string16 GetWindowTitle() const override;
+  base::string16 GetDialogButtonLabel(ui::DialogButton button) const override;
+
+  // views::WidgetDelegate interface.
+  views::View* GetContentsView() override;
+  views::Widget* GetWidget() override;
+  const views::Widget* GetWidget() const override;
+  void DeleteDelegate() override;
+
+  // Called by MessageBox::Core when it is destroyed.
+  void OnMessageBoxDestroyed();
+
+ private:
+  const base::string16 title_label_;
+  const base::string16 ok_label_;
+  const base::string16 cancel_label_;
+  ResultCallback result_callback_;
+  MessageBox* message_box_;
+
+  // Owned by the native widget hierarchy.
+  views::MessageBoxView* message_box_view_;
+
+  DISALLOW_COPY_AND_ASSIGN(Core);
+};
+
+MessageBox::Core::Core(const base::string16& title_label,
+                       const base::string16& message_label,
+                       const base::string16& ok_label,
+                       const base::string16& cancel_label,
+                       ResultCallback result_callback,
+                       MessageBox* message_box)
+    : title_label_(title_label),
+      ok_label_(ok_label),
+      cancel_label_(cancel_label),
+      result_callback_(result_callback),
+      message_box_(message_box),
+      message_box_view_(new views::MessageBoxView(
+          views::MessageBoxView::InitParams(message_label))) {
+  DCHECK(message_box_);
+}
+
+void MessageBox::Core::Show() {
+  // The widget is owned by the NativeWidget.  See  comments in widget.h.
+  views::Widget* widget =
+      CreateDialogWidget(this, /* delegate */
+                         nullptr /* parent window*/,
+                         nullptr /* parent view */);
+
+  if (widget) {
+    widget->Show();
+  }
+}
+
+void MessageBox::Core::Hide() {
+  if (GetWidget()) {
+    GetWidget()->Close();
+  }
+}
+
+bool MessageBox::Core::Accept() {
+  if (!result_callback_.is_null()) {
+    base::ResetAndReturn(&result_callback_).Run(OK);
+  }
+  return true /* close the window*/;
+}
+
+bool MessageBox::Core::Cancel() {
+  if (!result_callback_.is_null()) {
+    base::ResetAndReturn(&result_callback_).Run(CANCEL);
+  }
+  return true /* close the window*/;
+}
+
+ui::ModalType MessageBox::Core::GetModalType() const {
+  return ui::MODAL_TYPE_SYSTEM;
+}
+
+base::string16 MessageBox::Core::GetWindowTitle() const {
+  return title_label_;
+}
+
+base::string16 MessageBox::Core::GetDialogButtonLabel(
+    ui::DialogButton button) const {
+  switch (button) {
+    case ui::DIALOG_BUTTON_OK:
+      return ok_label_;
+    case ui::DIALOG_BUTTON_CANCEL:
+      return cancel_label_;
+    default:
+      NOTREACHED();
+      return base::string16();
+  }
+}
+
+views::View* MessageBox::Core::GetContentsView() {
+  return message_box_view_;
+}
+
+views::Widget* MessageBox::Core::GetWidget() {
+  return message_box_view_->GetWidget();
+}
+
+const views::Widget* MessageBox::Core::GetWidget() const {
+  return message_box_view_->GetWidget();
+}
+
+void MessageBox::Core::DeleteDelegate() {
+  if (message_box_) {
+    message_box_->core_ = nullptr;
+  }
+  delete this;
+}
+
+void MessageBox::Core::OnMessageBoxDestroyed() {
+  DCHECK(message_box_);
+  message_box_ = nullptr;
+  // The callback should not be invoked after MessageBox is destroyed.
+  result_callback_.Reset();
+}
+
+MessageBox::MessageBox(const base::string16& title_label,
+                       const base::string16& message_label,
+                       const base::string16& ok_label,
+                       const base::string16& cancel_label,
+                       ResultCallback result_callback)
+    : core_(new Core(title_label,
+                     message_label,
+                     ok_label,
+                     cancel_label,
+                     result_callback,
+                     this)) {
+  thread_checker_.DetachFromThread();
+}
+
+MessageBox::~MessageBox() {
+  if (core_) {
+    core_->OnMessageBoxDestroyed();
+    core_->Hide();
+    core_ = nullptr;
+  }
+}
+
+void MessageBox::Show() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  core_->Show();
+}
+
+void MessageBox::Hide() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (core_) {
+    core_->Hide();
+  }
+}
+
+}  // namespace remoting

remoting/host/chromeos/message_box.h

+// 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.
+
+#ifndef REMOTING_HOST_CHROMEOS_MESSAGE_BOX_H_
+#define REMOTING_HOST_CHROMEOS_MESSAGE_BOX_H_
+
+#include "base/callback_helpers.h"
+#include "base/strings/string16.h"
+#include "base/threading/thread_checker.h"
+
+namespace remoting {
+
+// Overview:
+// Shows a system modal message box with OK and cancel buttons. This class
+// is not thread-safe, it must be called on the UI thread of the browser
+// process.
+class MessageBox {
+ public:
+  enum Result {
+    OK,
+    CANCEL
+  };
+
+  // ResultCallback will be invoked with Result::Cancel if the user closes the
+  // MessageBox without clicking on any buttons.
+  typedef base::Callback<void(Result)> ResultCallback;
+
+  MessageBox(const base::string16& title_label,
+             const base::string16& message_label,
+             const base::string16& ok_label,
+             const base::string16& cancel_label,
+             ResultCallback result_callback);
+  ~MessageBox();
+
+  void Show();
+  void Hide();
+
+ private:
+  class Core;
+  Core* core_;
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(MessageBox);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_CHROMEOS_MESSAGE_BOX_H_

remoting/host/continue_window_chromeos.cc

@@ -4,41 +4,59 @@
 
 #include "remoting/host/continue_window.h"
 
+#include "remoting/base/string_resources.h"
+#include "remoting/host/chromeos/message_box.h"
+#include "ui/base/l10n/l10n_util.h"
+
 namespace remoting {
 
 namespace {
 
-// A place holder implementation for the ContinueWindow on
-// ChromeOS. Remote assistance on Chrome OS is currently under a flag so it is
-// secure to leave it unimplemented for now.
 class ContinueWindowAura : public ContinueWindow {
  public:
   ContinueWindowAura();
   ~ContinueWindowAura() override;
 
+  void OnMessageBoxResult(MessageBox::Result result);
+
  protected:
   // ContinueWindow interface.
   void ShowUi() override;
   void HideUi() override;
 
  private:
+  scoped_ptr<MessageBox> message_box_;
   DISALLOW_COPY_AND_ASSIGN(ContinueWindowAura);
 };
 
 ContinueWindowAura::ContinueWindowAura() {
+  message_box_.reset(new MessageBox(
+      l10n_util::GetStringUTF16(IDS_MODE_IT2ME),           // title
+      l10n_util::GetStringUTF16(IDS_CONTINUE_PROMPT),      // dialog label
+      l10n_util::GetStringUTF16(IDS_CONTINUE_BUTTON),      // ok label
+      l10n_util::GetStringUTF16(IDS_STOP_SHARING_BUTTON),  // cancel label
+      base::Bind(&ContinueWindowAura::OnMessageBoxResult,
+                 base::Unretained(this))));
 }
 
 ContinueWindowAura::~ContinueWindowAura() {
+  message_box_->Hide();
+}
+
+void ContinueWindowAura::OnMessageBoxResult(MessageBox::Result result) {
+  if (result == MessageBox::OK) {
+    ContinueSession();
+  } else {
+    DisconnectSession();
+  }
 }
 
 void ContinueWindowAura::ShowUi() {
-  // TODO(kelvinp): Implement this on Chrome OS (See crbug.com/424908).
-  NOTIMPLEMENTED();
+  message_box_->Show();
 }
 
 void ContinueWindowAura::HideUi() {
-  // TODO(kelvinp): Implement this on Chrome OS (See crbug.com/424908).
-  NOTIMPLEMENTED();
+  message_box_->Hide();
 }
 
 }  // namespace

remoting/remoting_host.gypi

@@ -74,6 +74,8 @@
             'host/capture_scheduler.h',
             'host/chromeos/aura_desktop_capturer.cc',
             'host/chromeos/aura_desktop_capturer.h',
+            'host/chromeos/message_box.cc',
+            'host/chromeos/message_box.h',
             'host/chromium_port_allocator_factory.cc',
             'host/chromium_port_allocator_factory.h',
             'host/chromoting_host.cc',
@@ -328,6 +330,8 @@
                 '../skia/skia.gyp:skia',
                 '../ui/aura/aura.gyp:aura',
                 '../ui/compositor/compositor.gyp:compositor',
+                '../ui/events/events.gyp:events',
+                '../ui/views/views.gyp:views',
               ],
               'include_dirs': [
                 '../third_party/skia/include/utils',
@@ -343,6 +347,8 @@
                'sources!' : [
                  'host/chromeos/aura_desktop_capturer.cc',
                  'host/chromeos/aura_desktop_capturer.h',
+                 'host/chromeos/message_box.cc',
+                 'host/chromeos/message_box.h',
                  'host/continue_window_chromeos.cc',
                  'host/disconnect_window_chromeos.cc',
                  'host/policy_hack/policy_watcher_chromeos.cc',