Revert 258077 "Remove PrepareForShutdown"

trunk/src/ash/display/screen_ash.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 "ash/display/screen_ash.h"
 
 #include "ash/display/display_controller.h"
 #include "ash/display/display_manager.h"
 #include "ash/root_window_controller.h"
 #include "ash/root_window_settings.h"
@@ skipping 214 matching lines @@
 std::vector<gfx::Display> ScreenAsh::GetAllDisplays() const {
   return GetDisplayManager()->displays();
 }
 
 gfx::Display ScreenAsh::GetDisplayNearestWindow(gfx::NativeView window) const {
   if (!window)
     return GetPrimaryDisplay();
   const aura::Window* root_window = window->GetRootWindow();
   if (!root_window)
     return GetPrimaryDisplay();
-  const internal::RootWindowSettings* rws =
-      internal::GetRootWindowSettings(root_window);
-  if (rws->shutdown)
-    return gfx::Display();
-  int64 id = rws->display_id;
+  int64 id = internal::GetRootWindowSettings(root_window)->display_id;
   // if id is |kInvaildDisplayID|, it's being deleted.
   DCHECK(id != gfx::Display::kInvalidDisplayID);
 
   internal::DisplayManager* display_manager = GetDisplayManager();
   // RootWindow needs Display to determine its device scale factor
   // for non desktop display.
   if (display_manager->non_desktop_display().id() == id)
     return display_manager->non_desktop_display();
   return display_manager->GetDisplayForId(id);
 }
@@ skipping 29 matching lines @@
 
 void ScreenAsh::RemoveObserver(gfx::DisplayObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 gfx::Screen* ScreenAsh::CloneForShutdown() {
   return new ScreenForShutdown(this);
 }
 
 }  // namespace ash