Add views::View::set_preferred_size, use it in a few places.

ash/system/screen_layout_observer.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/system/screen_layout_observer.h"
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "ash/display/screen_orientation_controller_chromeos.h"
 #include "ash/metrics/user_metrics_action.h"
 #include "ash/resources/grit/ash_resources.h"
 #include "ash/session/session_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/devicetype_utils.h"
 #include "ash/system/system_notifier.h"
-#include "ash/system/tray/fixed_sized_image_view.h"
 #include "ash/system/tray/system_tray_controller.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/wm/maximize_mode/maximize_mode_controller.h"
 #include "base/bind.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/display/display.h"
 #include "ui/display/manager/display_manager.h"
@@ skipping 375 matching lines @@
       return true;
 
     default:
       // Mirror mode was turned off; other messages should be shown e.g.
       // extended mode is on, ... etc.
       return false;
   }
 }
 
 }  // namespace ash