mash: Fold ShelfItemDelegateManager into ShelfModel

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 652a47fc570fd0e63eab64ec148ab48cfd9a36f8..b6b2035213e3191fc4c17f943cfe86ebf7d4762e 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -123,7 +123,6 @@ class ScreenPositionController;
 class SessionStateDelegate;
 class Shelf;
 class ShelfDelegate;
-class ShelfItemDelegateManager;
 class ShelfWindowWatcher;
 class ShellDelegate;
 struct ShellInitParams;
@@ -373,10 +372,6 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
     return activation_client_;
   }
 
-  ShelfItemDelegateManager* shelf_item_delegate_manager() {
-    return shelf_item_delegate_manager_.get();
-  }
-
   base::SequencedWorkerPool* blocking_pool() { return blocking_pool_; }
 
   // Force the shelf to query for it's current visibility state.
@@ -566,7 +561,6 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
   std::unique_ptr<NewWindowDelegate> new_window_delegate_;
   std::unique_ptr<PointerDownWatcherDelegate> pointer_down_watcher_delegate_;
   std::unique_ptr<ShelfDelegate> shelf_delegate_;
-  std::unique_ptr<ShelfItemDelegateManager> shelf_item_delegate_manager_;
   std::unique_ptr<ShelfWindowWatcher> shelf_window_watcher_;
   std::unique_ptr<WindowPositioner> window_positioner_;