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(){};
+  ~UIElementDelegate(){};

[sadrul, 2017/05/09 04:58:07]

Make the dtor virtual

You may need to move the bodies into the .cc file.

[thanhph, 2017/05/09 20:52:46]

Added. The dtor code runs ok here.

+
+  // |parent| adds |child| in DOM tree.
+  virtual void OnUIElementAdded(UIElement* parent, UIElement* child);

[sadrul, 2017/05/09 04:58:07]

These should be pure virtuals (i.e. = 0;)

[thanhph, 2017/05/09 20:52:46]

Done.

+
+  // Move |child| to different sibling location under |parent| in DOM tree.
+  virtual void OnUIElementReordered(UIElement* parent, UIElement* child);
+
+  // Add map tracking node id to element.
+  virtual void AddNodeIdMap(UIElement* ui_element);
+
+  // Remove map tracking node id to element.
+  virtual void RemoveNodeIdMap(UIElement* ui_element);

[sadrul, 2017/05/09 04:58:07]

AddNodeIdMap() And RemoveNodeIdMap() should not be in this interface.
UIElementDelegate should only have the methods necessary for a UIElement to talk
back to the DOMAgent. These methods related to the id-map are internal
implementation details of the DOMAgent, and so does not need to be in the
UIElementDelegate interface.

[thanhph, 2017/05/09 20:52:46]

Done. When ui_element is being constructed, the constructor will call
delegate()->OnUIElementAdded(0, this) which will initialize dom map.

void AshDevToolsDOMAgent::OnUIElementAdded(UIElement* parent,
                                           UIElement* child) {
  if (!parent) {
    node_id_to_ui_element_[child->node_id()] = child;
    return;
  }
  ....
}

Similarly, OnUIElementRemoved() will erase the map based on node_id.
 

+
+  // Retun true if element is sucessfully removed in DOM tree, false otherwise.
+  virtual bool OnUIElementRemoved(UIElement* ui_element);
+
+  // Update CSS agent when bounds change.
+  virtual void OnUIElementBoundsChanged(UIElement* ui_element);
+
+  // Return |window| highlighting status.
+  virtual bool IsHighlightingWindow(aura::Window* window);

[sadrul, 2017/05/09 04:58:07]

This feels a little bit weird here. We may be able to move it out of this in the
future, but for now, this is probably OK.

[thanhph, 2017/05/09 20:52:46]

Acknowledged.

+
+  DISALLOW_COPY_AND_ASSIGN(UIElementDelegate);
+};
+
+}  // namespace devtools
+}  // namespace ash
+
+#endif  // ASH_DEVTOOLS_UI_ELEMENT_DELEGATE_H_