Fix a bug of PopupAlignmentDelegate on non-primary display

ui/message_center/views/desktop_popup_alignment_delegate.cc

 // 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.
 
 #include "ui/message_center/views/desktop_popup_alignment_delegate.h"
 
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/message_center/message_center_style.h"
@@ skipping 28 matching lines @@
     return work_area_.x() + kMarginBetweenItems;
   return work_area_.right() - kMarginBetweenItems - toast_bounds.width();
 }
 
 int DesktopPopupAlignmentDelegate::GetBaseLine() const {
   return IsTopDown()
       ? work_area_.y() + kMarginBetweenItems
       : work_area_.bottom() - kMarginBetweenItems;
 }
 
-int DesktopPopupAlignmentDelegate::GetWorkAreaBottom() const {
-  return work_area_.bottom();
+gfx::Rect DesktopPopupAlignmentDelegate::GetWorkArea() const {
+  return work_area_;
 }
 
 bool DesktopPopupAlignmentDelegate::IsTopDown() const {
   return (alignment_ & POPUP_ALIGNMENT_TOP) != 0;
 }
 
 bool DesktopPopupAlignmentDelegate::IsFromLeft() const {
   return (alignment_ & POPUP_ALIGNMENT_LEFT) != 0;
 }
 
@@ skipping 58 matching lines @@
 void DesktopPopupAlignmentDelegate::OnDisplayMetricsChanged(
     const display::Display& display,
     uint32_t metrics) {
   // Set to kInvalidDisplayID so the alignment is updated regardless of whether
   // the primary display actually changed.
   primary_display_id_ = display::Display::kInvalidDisplayID;
   UpdatePrimaryDisplay();
 }
 
 }  // namespace message_center