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

ui/message_center/views/desktop_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 UI_MESSAGE_CENTER_VIEWS_DESKTOP_POPUP_ALIGNMENT_DELEGATE_H_
+#define UI_MESSAGE_CENTER_VIEWS_DESKTOP_POPUP_ALIGNMENT_DELEGATE_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 gfx {
+class Screen;
+}
+
+namespace message_center {
+namespace test {
+class MessagePopupCollectionTest;
+}
+
+// The PopupAlignmentDelegate for non-ash Windows/Linux desktop.
+class MESSAGE_CENTER_EXPORT DesktopPopupAlignmentDelegate
+    : public PopupAlignmentDelegate,
+      public gfx::DisplayObserver {
+ public:
+  DesktopPopupAlignmentDelegate();
+  virtual ~DesktopPopupAlignmentDelegate();
+
+  void StartObserving(gfx::Screen* screen);
+
+  // Overridden from 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 test::MessagePopupCollectionTest;
+
+  enum PopupAlignment {
+    POPUP_ALIGNMENT_TOP = 1 << 0,
+    POPUP_ALIGNMENT_LEFT = 1 << 1,
+    POPUP_ALIGNMENT_BOTTOM = 1 << 2,
+    POPUP_ALIGNMENT_RIGHT = 1 << 3,
+  };
+
+  // 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;
+
+  int32_t alignment_;
+  int64_t display_id_;
+  gfx::Screen* screen_;
+  gfx::Rect work_area_;
+
+  DISALLOW_COPY_AND_ASSIGN(DesktopPopupAlignmentDelegate);
+};
+
+}  // namespace message_center
+
+#endif  // UI_MESSAGE_CENTER_VIEWS_DESKTOP_POPUP_ALIGNMENT_DELEGATE_H_