Revert of Hook up views/widgets to AshDevToolsDOMAgent

ash/common/devtools/ash_devtools_dom_agent.h

 // Copyright 2016 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_COMMON_DEVTOOLS_ASH_DEVTOOLS_DOM_AGENT_H_
 #define ASH_COMMON_DEVTOOLS_ASH_DEVTOOLS_DOM_AGENT_H_
 
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window_observer.h"
 #include "base/compiler_specific.h"
 #include "components/ui_devtools/DOM.h"
 #include "components/ui_devtools/devtools_base_agent.h"
 #include "ui/views/view.h"
-#include "ui/views/view_observer.h"
 #include "ui/views/widget/widget.h"
-#include "ui/views/widget/widget_removals_observer.h"
 
 namespace ash {
 namespace devtools {
 
 class ASH_EXPORT AshDevToolsDOMAgent
     : public NON_EXPORTED_BASE(ui::devtools::UiDevToolsBaseAgent<
                                ui::devtools::protocol::DOM::Metainfo>),
-      public WmWindowObserver,
-      public views::WidgetRemovalsObserver,
-      public views::ViewObserver {
+      public WmWindowObserver {
  public:
   explicit AshDevToolsDOMAgent(ash::WmShell* shell);
   ~AshDevToolsDOMAgent() override;
 
   // DOM::Backend
   ui::devtools::protocol::Response disable() override;
   ui::devtools::protocol::Response getDocument(
       std::unique_ptr<ui::devtools::protocol::DOM::Node>* out_root) override;
 
   // WindowObserver
   void OnWindowTreeChanging(WmWindow* window,
                             const TreeChangeParams& params) override;
   void OnWindowTreeChanged(WmWindow* window,
                            const TreeChangeParams& params) override;
   void OnWindowStackingChanged(WmWindow* window) override;
 
-  // views::WidgetRemovalsObserver
-  void OnWillRemoveView(views::Widget* widget, views::View* view) override;
-
-  // views::ViewObserver
-  void OnChildViewRemoved(views::View* view, views::View* parent) override;
-  void OnChildViewAdded(views::View* view) override;
-  void OnChildViewReordered(views::View*) override;
-
   WmWindow* GetWindowFromNodeId(int nodeId);
   views::Widget* GetWidgetFromNodeId(int nodeId);
   views::View* GetViewFromNodeId(int nodeId);
 
   int GetNodeIdFromWindow(WmWindow* window);
   int GetNodeIdFromWidget(views::Widget* widget);
   int GetNodeIdFromView(views::View* view);
 
  private:
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildInitialTree();
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildTreeForWindow(
       WmWindow* window);
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildTreeForRootWidget(
       views::Widget* widget);
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildTreeForView(
       views::View* view);
 
   void AddWindowTree(WmWindow* window);
   // |remove_observer| ensures that we don't add a duplicate observer in any
   // observer callback. For example, |remove_observer| is false when rebuilding
   // the tree in OnWindowStackingChanged so that the observer is not removed and
   // re-added, thus causing endless calls on the observer.
   void RemoveWindowTree(WmWindow* window, bool remove_observer);
   void RemoveWindowNode(WmWindow* window, bool remove_observer);
 
-  // Don't need AddWidgetTree because |widget| will always be inside a window,
-  // so when windows are created, their widget nodes are created as well.
   void RemoveWidgetTree(views::Widget* widget, bool remove_observer);
   void RemoveWidgetNode(views::Widget* widget, bool remove_observer);
 
-  void AddViewTree(views::View* view);
   void RemoveViewTree(views::View* view,
                       views::View* parent,
                       bool remove_observer);
   void RemoveViewNode(views::View* view,
                       views::View* parent,
                       bool remove_observer);
 
-  void RemoveObservers();
+  void RemoveObserverFromAllWindows();
   void Reset();
 
   ash::WmShell* shell_;
 
   using WindowToNodeIdMap = std::unordered_map<WmWindow*, int>;
   WindowToNodeIdMap window_to_node_id_map_;
   using NodeIdToWindowMap = std::unordered_map<int, WmWindow*>;
   NodeIdToWindowMap node_id_to_window_map_;
 
   using WidgetToNodeIdMap = std::unordered_map<views::Widget*, int>;
   WidgetToNodeIdMap widget_to_node_id_map_;
   using NodeIdToWidgetMap = std::unordered_map<int, views::Widget*>;
   NodeIdToWidgetMap node_id_to_widget_map_;
 
   using ViewToNodeIdMap = std::unordered_map<views::View*, int>;
   ViewToNodeIdMap view_to_node_id_map_;
   using NodeIdToViewMap = std::unordered_map<int, views::View*>;
   NodeIdToViewMap node_id_to_view_map_;
 
   DISALLOW_COPY_AND_ASSIGN(AshDevToolsDOMAgent);
 };
 
 }  // namespace devtools
 }  // namespace ash
 
 #endif  // ASH_COMMON_DEVTOOLS_ASH_DEVTOOLS_DOM_AGENT_H_