Moves ShellObserver to ash/common

ash/shelf/shelf_layout_manager.h

 // Copyright 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.
 
 #ifndef ASH_SHELF_SHELF_LAYOUT_MANAGER_H_
 #define ASH_SHELF_SHELF_LAYOUT_MANAGER_H_
 
 #include <memory>
 #include <vector>
 
 #include "ash/ash_export.h"
 #include "ash/common/session/session_state_observer.h"
 #include "ash/common/shelf/shelf_types.h"
+#include "ash/common/shell_observer.h"
 #include "ash/common/wm/background_animator.h"
 #include "ash/common/wm/dock/docked_window_layout_manager_observer.h"
 #include "ash/common/wm/workspace/workspace_types.h"
 #include "ash/shelf/shelf.h"
-#include "ash/shell_observer.h"
 #include "ash/snap_to_pixel_layout_manager.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/wm/gestures/shelf_gesture_handler.h"
 #include "ash/wm/lock_state_observer.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
@@ skipping 376 matching lines @@
 
   std::unique_ptr<RootWindowControllerObserverImpl>
       root_window_controller_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfLayoutManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_LAYOUT_MANAGER_H_