Don't dispatch event after shutdown on AshWTHUnified

ash/display/display_controller.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/display/display_controller.h"
 
 #include <algorithm>
 #include <cmath>
 #include <map>
 
@@ skipping 613 matching lines @@
     const aura::Window* window,
     const gfx::Insets& insets) {
   const aura::Window* root_window = window->GetRootWindow();
   int64 id = GetRootWindowSettings(root_window)->display_id;
   // if id is |kInvaildDisplayID|, it's being deleted.
   DCHECK(id != gfx::Display::kInvalidDisplayID);
   return GetDisplayManager()->UpdateWorkAreaOfDisplay(id, insets);
 }
 
 void DisplayController::OnDisplayAdded(const gfx::Display& display) {
-  if (GetDisplayManager()->IsInUnifiedMode()) {
+#if defined(OS_CHROMEOS)
+  if (GetDisplayManager()->default_multi_display_mode() ==
+      DisplayManager::UNIFIED) {
     if (primary_display_id == gfx::Display::kInvalidDisplayID)
       primary_display_id = display.id();
     AshWindowTreeHost* ash_host =
         AddWindowTreeHostForDisplay(display, AshWindowTreeHostInitParams());
     RootWindowController::CreateForSecondaryDisplay(ash_host);
 
     if (primary_tree_host_for_replace_) {
       AshWindowTreeHost* to_delete = primary_tree_host_for_replace_;
       primary_tree_host_for_replace_ = nullptr;
       DeleteHost(to_delete);
+#ifndef NDEBUG
+      auto iter = std::find_if(
+          window_tree_hosts_.begin(), window_tree_hosts_.end(),
+          [to_delete](const std::pair<int64, AshWindowTreeHost*>& pair) {
+            return pair.second == to_delete;
+          });
+      DCHECK(iter == window_tree_hosts_.end());
+#endif
       // the host has already been removed from the window_tree_host_.
     }
-  }
-  // TODO(oshima): It should be possible to consolidate logic for
-  // unified and non unified, but I'm keeping them separated to minimize
-  // the risk in M44. I'll consolidate this in M45.
-  else if (primary_tree_host_for_replace_) {
+  } else
+#endif
+      // TODO(oshima): It should be possible to consolidate logic for
+      // unified and non unified, but I'm keeping them separated to minimize
+      // the risk in M44. I'll consolidate this in M45.
+      if (primary_tree_host_for_replace_) {
     DCHECK(window_tree_hosts_.empty());
     primary_display_id = display.id();
     window_tree_hosts_[display.id()] = primary_tree_host_for_replace_;
     GetRootWindowSettings(GetWindow(primary_tree_host_for_replace_))
         ->display_id = display.id();
     primary_tree_host_for_replace_ = nullptr;
     const DisplayInfo& display_info =
         GetDisplayManager()->GetDisplayInfo(display.id());
     AshWindowTreeHost* ash_host = window_tree_hosts_[display.id()];
     ash_host->AsWindowTreeHost()->SetBounds(display_info.bounds_in_native());
@@ skipping 202 matching lines @@
   Shell::GetInstance()->display_configurator_animation()
       ->StartFadeInAnimation();
 #endif
 }
 
 void DisplayController::SetMirrorModeAfterAnimation(bool mirror) {
   GetDisplayManager()->SetMirrorMode(mirror);
 }
 
 }  // namespace ash