mash: Fix content_browser shutdown crash if ash exits at the login screen

chrome/browser/chromeos/login/ui/login_display_host_impl.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 "chrome/browser/chromeos/login/ui/login_display_host_impl.h"
 
 #include <utility>
 #include <vector>
 
 #include "ash/common/wallpaper/wallpaper_controller.h"
@@ skipping 261 matching lines @@
       !login_screen_locales->GetString(0, &login_screen_locale))
     return std::string();
 
   return login_screen_locale;
 }
 
 void EnableSystemSoundsForAccessibility() {
   chromeos::AccessibilityManager::Get()->EnableSystemSounds(true);
 }
 
-// A login implementation of WidgetDelegate.
-class LoginWidgetDelegate : public views::WidgetDelegate {
- public:
-  explicit LoginWidgetDelegate(views::Widget* widget) : widget_(widget) {
-  }
-  ~LoginWidgetDelegate() override {}
-
-  // Overridden from WidgetDelegate:
-  void DeleteDelegate() override { delete this; }
-  views::Widget* GetWidget() override { return widget_; }
-  const views::Widget* GetWidget() const override { return widget_; }
-  bool CanActivate() const override { return true; }
-  bool ShouldAdvanceFocusToTopLevelWidget() const override { return true; }
-
- private:
-  views::Widget* widget_;
-
-  DISALLOW_COPY_AND_ASSIGN(LoginWidgetDelegate);
-};
-
 // Disables virtual keyboard overscroll. Login UI will scroll user pods
 // into view on JS side when virtual keyboard is shown.
 void DisableKeyboardOverscroll() {
   keyboard::SetKeyboardOverscrollOverride(
       keyboard::KEYBOARD_OVERSCROLL_OVERRIDE_DISABLED);
 }
 
 void ResetKeyboardOverscrollOverride() {
   keyboard::SetKeyboardOverscrollOverride(
       keyboard::KEYBOARD_OVERSCROLL_OVERRIDE_NONE);
 }
 
 }  // namespace
 
 namespace chromeos {
 
 // static
 const int LoginDisplayHostImpl::kShowLoginWebUIid = 0x1111;
 
+// A login implementation of WidgetDelegate.
+class LoginDisplayHostImpl::LoginWidgetDelegate : public views::WidgetDelegate {
+ public:
+  LoginWidgetDelegate(views::Widget* widget, LoginDisplayHostImpl* host)
+      : widget_(widget), login_display_host_(host) {
+    DCHECK(widget_);
+    DCHECK(login_display_host_);
+  }
+  ~LoginWidgetDelegate() override {}
+
+  // Overridden from WidgetDelegate:
+  void WindowClosing() override {
+    // Reset the cached Widget and View pointers. The Widget may close due to:
+    // * Login completion
+    // * Ash crash at the login screen on mustash
+    // In the latter case the mash root process will trigger a clean restart
+    // of content_browser.
+    if (chrome::IsRunningInMash())
+      login_display_host_->ResetLoginWindowAndView();
+  }
+  void DeleteDelegate() override { delete this; }
+  views::Widget* GetWidget() override { return widget_; }
+  const views::Widget* GetWidget() const override { return widget_; }
+  bool CanActivate() const override { return true; }
+  bool ShouldAdvanceFocusToTopLevelWidget() const override { return true; }
+
+ private:
+  views::Widget* widget_;
+  LoginDisplayHostImpl* login_display_host_;
+
+  DISALLOW_COPY_AND_ASSIGN(LoginWidgetDelegate);
+};
+
 ////////////////////////////////////////////////////////////////////////////////
 // LoginDisplayHostImpl, public
 
 LoginDisplayHostImpl::LoginDisplayHostImpl(const gfx::Rect& wallpaper_bounds)
     : wallpaper_bounds_(wallpaper_bounds),
       pointer_factory_(this),
       animation_weak_ptr_factory_(this) {
   if (chrome::IsRunningInMash()) {
     // Animation, and initializing hidden, are not currently supported for Mash.
     finalize_animation_type_ = ANIMATION_NONE;
@@ skipping 868 matching lines @@
     params.parent =
         ash::Shell::GetContainer(ash::Shell::GetPrimaryRootWindow(),
                                  ash::kShellWindowId_LockScreenContainer);
   } else {
     using ui::mojom::WindowManager;
     params.mus_properties[WindowManager::kContainerId_InitProperty] =
         mojo::ConvertTo<std::vector<uint8_t>>(
             ash::kShellWindowId_LockScreenContainer);
   }
   login_window_ = new views::Widget;
-  params.delegate = new LoginWidgetDelegate(login_window_);
+  params.delegate = new LoginWidgetDelegate(login_window_, this);
   login_window_->Init(params);
 
   login_view_ = new WebUILoginView(WebUILoginView::WebViewSettings());
   login_view_->Init();
   if (login_view_->webui_visible())
     OnLoginPromptVisible();
 
   // Animations are not available in Mash
   if (!chrome::IsRunningInMash()) {
     login_window_->SetVisibilityAnimationDuration(
@@ skipping 123 matching lines @@
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kNaturalScrollDefault));
 
   gfx::Rect screen_bounds(chromeos::CalculateScreenBounds(gfx::Size()));
 
   session_manager::SessionManager::Get()->SetSessionState(
       StartupUtils::IsOobeCompleted()
           ? session_manager::SessionState::LOGIN_PRIMARY
           : session_manager::SessionState::OOBE);
 
+  // Manages its own lifetime. See ShutdownDisplayHost().
   LoginDisplayHostImpl* display_host = new LoginDisplayHostImpl(screen_bounds);
 
   bool show_app_launch_splash_screen =
       (first_screen == OobeScreen::SCREEN_APP_LAUNCH_SPLASH);
   if (show_app_launch_splash_screen) {
     const std::string& auto_launch_app_id =
         KioskAppManager::Get()->GetAutoLaunchApp();
     const bool diagnostic_mode = false;
     const bool auto_launch = true;
     display_host->StartAppLaunch(auto_launch_app_id,
@@ skipping 75 matching lines @@
   // Chrome locale. Otherwise it will be lost if Chrome restarts.
   // Don't need to schedule pref save because setting initial local
   // will enforce preference saving.
   prefs->SetString(prefs::kApplicationLocale, locale);
   StartupUtils::SetInitialLocale(locale);
 
   TriggerShowLoginWizardFinish(locale, std::move(data));
 }
 
 }  // namespace chromeos