Adds AppListDelegate to AppList that is notified on visibility changes

ui/app_list/presenter/app_list.h

 // Copyright 2016 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 UI_APP_LIST_PRESENTER_APP_LIST_H_
 #define UI_APP_LIST_PRESENTER_APP_LIST_H_
 
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "ui/app_list/presenter/app_list_presenter.mojom.h"
 #include "ui/app_list/presenter/app_list_presenter_export.h"
 
 namespace app_list {
 
+class AppListDelegate;
+
 // Stores the app list presenter interface pointer.
 class APP_LIST_PRESENTER_EXPORT AppList : public mojom::AppList {
  public:
   AppList();
   ~AppList() override;
 
   // Binds the mojom::AppList interface request to this object.
   void BindRequest(mojom::AppListRequest request);
 
   // Get a raw pointer to the mojom::AppListPresenter interface; may be null.
   mojom::AppListPresenter* GetAppListPresenter();
 
   // Helper functions to call the underlying functionality on the presenter.
   void Show(int64_t display_id);
   void Dismiss();
   void ToggleAppList(int64_t display_id);
 
   // Helper functions to get the cached state as reported by the presenter.
   bool IsVisible() const;
   bool GetTargetVisibility() const;
 
   // mojom::AppList:
   void SetAppListPresenter(mojom::AppListPresenterPtr presenter) override;
   void OnTargetVisibilityChanged(bool visible) override;
-  void OnVisibilityChanged(bool visible) override;
+  void OnVisibilityChanged(bool visible, int64_t display_id) override;
+
+  void set_delegate(AppListDelegate* delegate) { delegate_ = delegate; }
 
  private:
   // Bindings for the mojom::AppList interface.
   mojo::BindingSet<mojom::AppList> bindings_;
 
   // App list presenter interface in chrome; used to show/hide the app list.
   mojom::AppListPresenterPtr presenter_;
 
   // The cached [target] visibility, as reported by the presenter.
   bool target_visible_ = false;
   bool visible_ = false;
 
+  AppListDelegate* delegate_ = nullptr;
+
   DISALLOW_COPY_AND_ASSIGN(AppList);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_PRESENTER_APP_LIST_H_