Move shelf item tooltip flag from delegate to item.

ash/common/shelf/shelf_window_watcher.h

 // Copyright 2013 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_COMMON_SHELF_SHELF_WINDOW_WATCHER_H_
 #define ASH_COMMON_SHELF_SHELF_WINDOW_WATCHER_H_
 
 #include <set>
 
 #include "ash/common/wm_activation_observer.h"
@@ skipping 42 matching lines @@
   class UserWindowObserver : public WmWindowObserver {
    public:
     explicit UserWindowObserver(ShelfWindowWatcher* window_watcher);
     ~UserWindowObserver() override;
 
    private:
     // WmWindowObserver:
     void OnWindowPropertyChanged(WmWindow* window,
                                  WmWindowProperty property) override;
     void OnWindowDestroying(WmWindow* window) override;
+    void OnWindowVisibilityChanged(WmWindow* window, bool visible) override;
 
     ShelfWindowWatcher* window_watcher_;
 
     DISALLOW_COPY_AND_ASSIGN(UserWindowObserver);
   };
 
   // Creates a ShelfItem for |window|.
   void AddShelfItem(WmWindow* window);
 
   // Removes a ShelfItem for |window|.
@@ skipping 35 matching lines @@
 
   // The set of windows with shelf items managed by this ShelfWindowWatcher.
   std::set<WmWindow*> user_windows_with_items_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfWindowWatcher);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_SHELF_WINDOW_WATCHER_H_