Separate the logic of popup alignment and workarea handling as delegate.

ash/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_SYSTEM_WEB_NOTIFICATION_ASH_POPUP_ALIGNMENT_DELEGATE_H_
+#define ASH_SYSTEM_WEB_NOTIFICATION_ASH_POPUP_ALIGNMENT_DELEGATE_H_
+
+#include "ash/ash_export.h"
+#include "ash/shelf/shelf_layout_manager_observer.h"
+#include "ash/shelf/shelf_types.h"
+#include "ash/shell_observer.h"
+#include "base/macros.h"
+#include "ui/gfx/display_observer.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/message_center/views/popup_alignment_delegate.h"
+
+namespace aura {
+class Window;
+}
+
+namespace gfx {
+class Screen;
+}
+
+namespace ash {
+
+class AshPopupAlignmentDelegateTest;
+class ShelfLayoutManager;
+class WebNotificationTrayTest;
+
+// The PopupAlignmentDelegate subclass for Ash. It needs to handle alignment of
+// the shelf and its autohide state.
+class ASH_EXPORT AshPopupAlignmentDelegate
+    : public message_center::PopupAlignmentDelegate,
+      public ShelfLayoutManagerObserver,
+      public ShellObserver,
+      public gfx::DisplayObserver {
+ public:
+  AshPopupAlignmentDelegate();
+  virtual ~AshPopupAlignmentDelegate();
+
+  // Start observing the system.
+  void StartObserving(gfx::Screen* screen, const gfx::Display& display);
+
+  // Sets the current height of the system tray so that the notification toasts
+  // can avoid it.
+  void SetSystemTrayHeight(int height);
+
+  // Overridden from message_center::PopupAlignmentDelegate:
+  virtual int GetToastOriginX(const gfx::Rect& toast_bounds) const OVERRIDE;
+  virtual int GetBaseLine() const OVERRIDE;
+  virtual int GetWorkAreaBottom() const OVERRIDE;
+  virtual bool IsTopDown() const OVERRIDE;
+  virtual bool IsFromLeft() const OVERRIDE;
+  virtual void RecomputeAlignment(const gfx::Display& display) OVERRIDE;
+
+ private:
+  friend class AshPopupAlignmentDelegateTest;
+  friend class WebNotificationTrayTest;
+
+  // Get the current alignment of the shelf.
+  ShelfAlignment GetAlignment() const;
+
+  // Update |shelf_| and start watching when it's first set. This should not
+  // be done in the constructor because the shelf might not be initialized at
+  // that point.
+  void UpdateShelf();
+
+  // Overridden from ShellObserver:
+  virtual void OnDisplayWorkAreaInsetsChanged() OVERRIDE;
+
+  // Overridden from ShelfLayoutManagerObserver:
+  virtual void OnAutoHideStateChanged(ShelfAutoHideState new_state) OVERRIDE;
+
+  // Overridden from gfx::DisplayObserver:
+  virtual void OnDisplayAdded(const gfx::Display& new_display) OVERRIDE;
+  virtual void OnDisplayRemoved(const gfx::Display& old_display) OVERRIDE;
+  virtual void OnDisplayMetricsChanged(const gfx::Display& display,
+                                       uint32_t metrics) OVERRIDE;
+
+  int64_t display_id_;
+  gfx::Screen* screen_;
+  gfx::Rect work_area_;
+  aura::Window* root_window_;
+  ShelfLayoutManager* shelf_;
+  int system_tray_height_;
+
+  DISALLOW_COPY_AND_ASSIGN(AshPopupAlignmentDelegate);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_WEB_NOTIFICATION_ASH_POPUP_ALIGNMENT_DELEGATE_H_