Create a unified UIElement interface for Widget, View and Window.

ash/devtools/ui_element_delegate.h

+// Copyright 2017 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_DEVTOOLS_UI_ELEMENT_DELEGATE_H_
+#define ASH_DEVTOOLS_UI_ELEMENT_DELEGATE_H_
+
+#include <vector>
+
+#include "ash/ash_export.h"
+#include "base/macros.h"
+#include "ui/aura/window.h"
+
+namespace ash {
+namespace devtools {
+
+class UIElement;
+
+class ASH_EXPORT UIElementDelegate {
+ public:
+  UIElementDelegate(){};
+  virtual ~UIElementDelegate(){};
+
+  // |parent| adds |child| in DOM tree.

[sadrul, 2017/05/17 21:54:14]

You can remove these comments.

[thanhph, 2017/05/18 14:28:16]

Done.

+  virtual void OnUIElementAdded(UIElement* parent, UIElement* child) = 0;
+
+  // Move |child| to different sibling index under |parent| in DOM tree.
+  virtual void OnUIElementReordered(UIElement* parent, UIElement* child) = 0;
+
+  // Remove ui_element in DOM tree.
+  virtual void OnUIElementRemoved(UIElement* ui_element) = 0;
+
+  // Update CSS agent when bounds change.
+  virtual void OnUIElementBoundsChanged(UIElement* ui_element) = 0;
+
+  // Return |window| highlighting status.
+  virtual bool IsHighlightingWindow(aura::Window* window) = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(UIElementDelegate);
+};
+
+}  // namespace devtools
+}  // namespace ash
+
+#endif  // ASH_DEVTOOLS_UI_ELEMENT_DELEGATE_H_