Keep the SystemModalContainerEventHandler added

ash/shell.cc

 // Copyright (c) 2012 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/shell.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 483 matching lines @@
                     OnShelfAutoHideBehaviorChanged(root_window));
 }
 
 void Shell::NotifyFullscreenStateChange(bool is_fullscreen,
                                         WmWindow* root_window) {
   FOR_EACH_OBSERVER(ShellObserver, *wm_shell_->shell_observers(),
                     OnFullscreenStateChanged(is_fullscreen, root_window));
 }
 
 void Shell::CreateModalBackground(aura::Window* window) {
-  if (!modality_filter_) {
-    modality_filter_.reset(new SystemModalContainerEventFilter(this));
-    AddPreTargetHandler(modality_filter_.get());
-  }
   RootWindowControllerList controllers = GetAllRootWindowControllers();
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end(); ++iter)
     (*iter)->GetSystemModalLayoutManager(window)->CreateModalBackground();
 }
 
 void Shell::OnModalWindowRemoved(aura::Window* removed) {
   RootWindowControllerList controllers = GetAllRootWindowControllers();
   bool activated = false;
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end() && !activated; ++iter) {
     activated = (*iter)
                     ->GetSystemModalLayoutManager(removed)
                     ->ActivateNextModalWindow();
   }
   if (!activated) {
-    RemovePreTargetHandler(modality_filter_.get());
-    modality_filter_.reset();
     for (RootWindowControllerList::iterator iter = controllers.begin();
          iter != controllers.end(); ++iter)
       (*iter)->GetSystemModalLayoutManager(removed)->DestroyModalBackground();
   }
 }
 
 WebNotificationTray* Shell::GetWebNotificationTray() {
   return GetPrimaryRootWindowController()
       ->shelf_widget()
       ->status_area_widget()
@@ skipping 115 matching lines @@
   speech_feedback_handler_.reset();
 #endif
   RemovePreTargetHandler(overlay_filter_.get());
   RemovePreTargetHandler(accelerator_filter_.get());
   RemovePreTargetHandler(event_transformation_handler_.get());
   RemovePreTargetHandler(toplevel_window_event_handler_.get());
   RemovePostTargetHandler(toplevel_window_event_handler_.get());
   RemovePreTargetHandler(system_gesture_filter_.get());
   RemovePreTargetHandler(keyboard_metrics_filter_.get());
   RemovePreTargetHandler(mouse_cursor_filter_.get());
+  RemovePreTargetHandler(modality_filter_.get());
 
   // TooltipController is deleted with the Shell so removing its references.
   RemovePreTargetHandler(tooltip_controller_.get());
 
 #if defined(OS_CHROMEOS)
   screen_orientation_controller_.reset();
 #endif
 
 // Destroy the virtual keyboard controller before the maximize mode controller
 // since the latters destructor triggers events that the former is listening
@@ skipping 74 matching lines @@
   lock_state_controller_.reset();
 
   screen_pinning_controller_.reset();
 
 #if defined(OS_CHROMEOS)
   resolution_notification_controller_.reset();
 #endif
   desktop_background_controller_.reset();
   screenshot_controller_.reset();
   mouse_cursor_filter_.reset();
 

[oshima, 2016/07/14 21:49:41]

reset the event handler here.

 #if defined(OS_CHROMEOS)
   touch_transformer_controller_.reset();
 #endif  // defined(OS_CHROMEOS)
 
 #if defined(OS_CHROMEOS)
   audio_a11y_controller_.reset();
 #endif  // defined(OS_CHROMEOS)
 
   // This also deletes all RootWindows. Note that we invoke Shutdown() on
   // WindowTreeHostManager before resetting |window_tree_host_manager_|, since
@@ skipping 231 matching lines @@
   autoclick_controller_.reset(AutoclickController::CreateInstance());
 
   high_contrast_controller_.reset(new HighContrastController);
   video_detector_.reset(new VideoDetector);
   window_cycle_controller_.reset(new WindowCycleController());
 
   tooltip_controller_.reset(new views::corewm::TooltipController(
       std::unique_ptr<views::corewm::Tooltip>(new views::corewm::TooltipAura)));
   AddPreTargetHandler(tooltip_controller_.get());
 
+  modality_filter_.reset(new SystemModalContainerEventFilter(this));
+  AddPreTargetHandler(modality_filter_.get());
+
   event_client_.reset(new EventClientImpl);
 
   // This controller needs to be set before SetupManagedWindowMode.
   desktop_background_controller_.reset(
       new DesktopBackgroundController(blocking_pool_));
   user_wallpaper_delegate_.reset(
       wm_shell_->delegate()->CreateUserWallpaperDelegate());
 
   session_state_delegate_.reset(
       wm_shell_->delegate()->CreateSessionStateDelegate());
@@ skipping 151 matching lines @@
 
 void Shell::OnWindowActivated(
     aura::client::ActivationChangeObserver::ActivationReason reason,
     aura::Window* gained_active,
     aura::Window* lost_active) {
   if (gained_active)
     target_root_window_ = gained_active->GetRootWindow();
 }
 
 }  // namespace ash