Fix a bug of PopupAlignmentDelegate on non-primary display

ash/common/system/web_notification/ash_popup_alignment_delegate.h

 // Copyright 2014 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_SYSTEM_WEB_NOTIFICATION_ASH_POPUP_ALIGNMENT_DELEGATE_H_
 #define ASH_COMMON_SYSTEM_WEB_NOTIFICATION_ASH_POPUP_ALIGNMENT_DELEGATE_H_
 
 #include <stdint.h>
 
 #include "ash/ash_export.h"
@@ skipping 33 matching lines @@
   // Sets the current height of the system tray bubble (or legacy notification
   // bubble) so that web notification toasts can avoid it.
   void SetTrayBubbleHeight(int height);
 
   // Returns the current tray bubble height or 0 if there is no bubble.
   int tray_bubble_height_for_test() const { return tray_bubble_height_; }
 
   // Overridden from message_center::PopupAlignmentDelegate:
   int GetToastOriginX(const gfx::Rect& toast_bounds) const override;
   int GetBaseLine() const override;
-  int GetWorkAreaBottom() const override;
+  gfx::Rect GetWorkArea() const override;
   bool IsTopDown() const override;
   bool IsFromLeft() const override;
   void RecomputeAlignment(const display::Display& display) override;
   void ConfigureWidgetInitParamsForContainer(
       views::Widget* widget,
       views::Widget::InitParams* init_params) override;
 
  private:
   friend class AshPopupAlignmentDelegateTest;
   friend class WebNotificationTrayTest;
@@ skipping 21 matching lines @@
   gfx::Rect work_area_;
   WmShelf* shelf_;
   int tray_bubble_height_;
 
   DISALLOW_COPY_AND_ASSIGN(AshPopupAlignmentDelegate);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_WEB_NOTIFICATION_ASH_POPUP_ALIGNMENT_DELEGATE_H_