Move DevTools out of ash and turn it to a component.

ash/devtools/view_element.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_VIEW_ELEMENT_H_
-#define ASH_DEVTOOLS_VIEW_ELEMENT_H_
-
-#include "ash/ash_export.h"
-#include "ash/devtools/ui_element.h"
-#include "base/macros.h"
-#include "ui/aura/window.h"
-#include "ui/gfx/geometry/rect.h"
-#include "ui/views/view.h"
-#include "ui/views/view_observer.h"
-
-namespace ash {
-namespace devtools {
-
-class UIElementDelegate;
-
-class ASH_EXPORT ViewElement : public views::ViewObserver, public UIElement {
- public:
-  ViewElement(views::View* view,
-              UIElementDelegate* ui_element_delegate,
-              UIElement* parent);
-  ~ViewElement() override;
-  views::View* view() const { return view_; };
-
-  // views::ViewObserver
-  void OnChildViewRemoved(views::View* parent, views::View* view) override;
-  void OnChildViewAdded(views::View* parent, views::View* view) override;
-  void OnChildViewReordered(views::View* parent, views::View*) override;
-  void OnViewBoundsChanged(views::View* view) override;
-
-  // UIElement:
-  void GetBounds(gfx::Rect* bounds) const override;
-  void SetBounds(const gfx::Rect& bounds) override;
-  void GetVisible(bool* visible) const override;
-  void SetVisible(bool visible) override;
-  std::pair<aura::Window*, gfx::Rect> GetNodeWindowAndBounds() const override;
-  static views::View* From(UIElement* element);
-
- private:
-  views::View* view_;
-
-  DISALLOW_COPY_AND_ASSIGN(ViewElement);
-};
-
-}  // namespace devtools
-}  // namespace ash
-
-#endif  // ASH_DEVTOOLS_VIEW_ELEMENT_H_