Re-reland: chromeos: Fix shelf appearing at login screen under mash

ash/common/shelf/shelf_widget.h

 // 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.
 
 #ifndef ASH_COMMON_SHELF_SHELF_WIDGET_H_
 #define ASH_COMMON_SHELF_SHELF_WIDGET_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 11 matching lines @@
 
 namespace ash {
 class AppListButton;
 class FocusCycler;
 class ShelfLayoutManager;
 class ShelfView;
 class StatusAreaWidget;
 class WmShelf;
 class WmWindow;
 
+// The ShelfWidget manages the shelf view (which contains the shelf icons) and
+// the status area widget. There is one ShelfWidget per display. It is created
+// early during RootWindowController initialization.
 class ASH_EXPORT ShelfWidget : public views::Widget,
                                public views::WidgetObserver,
                                public ShelfBackgroundAnimatorObserver,
                                public ShelfLayoutManagerObserver {
  public:
   ShelfWidget(WmWindow* shelf_container, WmShelf* wm_shelf);
   ~ShelfWidget() override;
 
   void CreateStatusAreaWidget(WmWindow* status_container);
 
   void OnShelfAlignmentChanged();
 
   // DEPRECATED: Prefer WmShelf::GetAlignment().
   ShelfAlignment GetAlignment() const;
 
   // Sets the shelf's background type.
   void SetPaintsBackground(ShelfBackgroundType background_type,
                            BackgroundAnimatorChangeType change_type);
   ShelfBackgroundType GetBackgroundType() const;
 
   // Hide the shelf behind a black bar during e.g. a user transition when |hide|
   // is true. The |animation_time_ms| will be used as animation duration.
   void HideShelfBehindBlackBar(bool hide, int animation_time_ms);
   bool IsShelfHiddenBehindBlackBar() const;
 
   ShelfLayoutManager* shelf_layout_manager() { return shelf_layout_manager_; }
   StatusAreaWidget* status_area_widget() const { return status_area_widget_; }
 
+  // Creates the shelf view and populates it with icons. Called after the user
+  // session is active (and hence the user profile is available).
   ShelfView* CreateShelfView();
   void PostCreateShelf();
 
-  // Set visibility of the shelf.
-  void SetShelfVisibility(bool visible);
   bool IsShelfVisible() const;
 
   bool IsShowingAppList() const;
   bool IsShowingContextMenu() const;
   bool IsShowingOverflowBubble() const;
 
   // Sets the focus cycler.  Also adds the shelf to the cycle.
   void SetFocusCycler(FocusCycler* focus_cycler);
   FocusCycler* GetFocusCycler();
 
@@ skipping 33 matching lines @@
 
   // Owned by the shelf container's window.
   ShelfLayoutManager* shelf_layout_manager_;
 
   // Owned by the native widget.
   StatusAreaWidget* status_area_widget_;
 
   // |delegate_view_| is the contents view of this widget and is cleaned up
   // during CloseChildWindows of the associated RootWindowController.
   DelegateView* delegate_view_;
-  // View containing the shelf items. Owned by the views hierarchy.
+  // View containing the shelf items. Owned by the views hierarchy. Null when
+  // at the login screen.
   ShelfView* shelf_view_;
   ShelfBackgroundAnimator background_animator_;
   bool activating_as_fallback_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfWidget);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_SHELF_WIDGET_H_