arc: Add Arc Kiosk app service and ability to launch kiosk apps.

chrome/browser/chromeos/app_mode/arc/arc_kiosk_app_launcher.cc

+// Copyright 2016 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/chromeos/app_mode/arc/arc_kiosk_app_launcher.h>
+
+#include "ash/wm/window_util.h"
+#include "chrome/browser/ui/app_list/arc/arc_app_utils.h"
+#include "chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.h"
+#include "ui/aura/env.h"
+
+namespace chromeos {
+
+ArcKioskAppLauncher::ArcKioskAppLauncher(content::BrowserContext* context,
+                                         const std::string& app_id)
+    : app_id_(app_id) {
+  prefs_ = ArcAppListPrefs::Get(context);
+  prefs_->AddObserver(this);
+  aura::Env::GetInstance()->AddObserver(this);
+  // Launching the app by app id in landscape mode.
+  arc::LaunchApp(context, app_id_);
+}
+
+ArcKioskAppLauncher::~ArcKioskAppLauncher() {
+  StopObserving();
+}
+
+void ArcKioskAppLauncher::OnTaskCreated(int32_t task_id,
+                                        const std::string& package_name,
+                                        const std::string& activity) {
+  std::unique_ptr<ArcAppListPrefs::AppInfo> app = prefs_->GetApp(app_id_);
+  if (!app || app->package_name != package_name || app->activity != activity)
+    return;
+  task_id_ = task_id;
+  // The app window may have been created already.
+  for (aura::Window* window : windows_) {
+    if (CheckWindow(window))
+      break;
+  }
+}
+
+void ArcKioskAppLauncher::OnWindowInitialized(aura::Window* window) {
+  // The |window|’s task ID is not set yet. We need to observe
+  // the window until the |kApplicationIdKey| property is set.
+  window->AddObserver(this);
+  windows_.insert(window);
+}
+
+void ArcKioskAppLauncher::OnWindowPropertyChanged(aura::Window* window,
+                                                  const void* key,
+                                                  intptr_t old) {
+  // If we do not know yet what task ID to look for, do nothing.
+  // Existing windows will be revisited the moment the task ID
+  // becomes known.
+  if (task_id_ == -1)
+    return;
+
+  // We are only interested in changes to |kApplicationIdKey|,
+  // but that constant is not accessible outside shell_surface.cc.
+  // So we react to all property changes.
+  CheckWindow(window);
+}
+
+void ArcKioskAppLauncher::OnWindowDestroying(aura::Window* window) {
+  window->RemoveObserver(this);
+  windows_.erase(window);
+}
+
+bool ArcKioskAppLauncher::CheckWindow(aura::Window* const window) {
+  DCHECK_GE(task_id_, 0);
+  if (ArcAppWindowLauncherController::GetWindowTaskId(window) != task_id_)
+    return false;
+  // Stop observing as target window is already found.
+  StopObserving();
+  ash::wm::PinWindow(window, true);

[Nikita (slow), 2016/11/16 15:33:28]

nit: true /* trusted */

[Sergey Poromov, 2016/11/16 15:54:09]

Done.

+  return true;
+}
+
+void ArcKioskAppLauncher::StopObserving() {
+  aura::Env::GetInstance()->RemoveObserver(this);
+  for (auto* window : windows_)
+    window->RemoveObserver(this);
+  windows_.clear();
+  prefs_->RemoveObserver(this);
+}
+
+}  // namespace chromeos