Replace Ash web notification tray view with a button.

ash/system/tray/tray_background_view.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_SYSTEM_TRAY_TRAY_BACKGROUND_VIEW_H_
 #define ASH_SYSTEM_TRAY_TRAY_BACKGROUND_VIEW_H_
 
 #include "ash/ash_export.h"
 #include "ash/launcher/background_animator.h"
 #include "ash/system/tray/tray_views.h"
@@ skipping 38 matching lines @@
 
    private:
     void UpdateLayout();
 
     ShelfAlignment alignment_;
     gfx::Size size_;
 
     DISALLOW_COPY_AND_ASSIGN(TrayContainer);
   };
 
-  explicit TrayBackgroundView(internal::StatusAreaWidget* status_area_widget);
+  TrayBackgroundView(internal::StatusAreaWidget* status_area_widget,
+                              bool set_background);

[tfarina, 2012/08/26 22:17:59]

nit: fix indentation here.

   virtual ~TrayBackgroundView();
 
   // Called after the tray has been added to the widget containing it.
   virtual void Initialize();
 
   // Overridden from views::View.
   virtual void OnMouseEntered(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
   virtual void ChildPreferredSizeChanged(views::View* child) OVERRIDE;
   virtual void OnPaintFocusBorder(gfx::Canvas* canvas) OVERRIDE;
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
   virtual void AboutToRequestFocusFromTabTraversal(bool reverse) OVERRIDE;
 
   // Overridden from internal::ActionableView.
   virtual bool PerformAction(const ui::Event& event) OVERRIDE;
 
   // Overridden from internal::BackgroundAnimatorDelegate.
   virtual void UpdateBackground(int alpha) OVERRIDE;
 
   // Called whenever the shelf alignment changes.
   virtual void SetShelfAlignment(ShelfAlignment alignment);
 
   // Called when the anchor (tray or bubble) may have moved or changed.
   virtual void AnchorUpdated() {}
 
   virtual string16 GetAccessibleName() = 0;
 
-  // Sets |contents| as a child and sets its background to |background_|.
-  void SetContents(views::View* contents);
+  // Sets |contents| as a child. If |set_background| is true, also creates and
+  // sets |background_|.
+  void SetContents(views::View* contents, bool set_background);
 
   // Sets whether the tray paints a background. Default is true, but is set to
   // false if a window overlaps the shelf.
   void SetPaintsBackground(
       bool value,
       internal::BackgroundAnimator::ChangeType change_type);
 
   // Convenience function to call same function in status_area_widget_.
   void UpdateShouldShowLauncher();
 
@@ skipping 27 matching lines @@
   scoped_ptr<internal::TrayLayerAnimationObserver>
       layer_animation_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayBackgroundView);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_TRAY_BACKGROUND_VIEW_H_