Fix bug where removed (but not deleted) windows are not reflected in the tree properly

ash/common/devtools/ash_devtools_dom_agent.h

Index: ash/common/devtools/ash_devtools_dom_agent.h
diff --git a/ash/common/devtools/ash_devtools_dom_agent.h b/ash/common/devtools/ash_devtools_dom_agent.h
index 760671f742105bb36dad4908993ab72fae3a4a7d..f4e90a286ac3519ba897183ca85de5a5288b6de6 100644
--- a/ash/common/devtools/ash_devtools_dom_agent.h
+++ b/ash/common/devtools/ash_devtools_dom_agent.h
@@ -28,7 +28,8 @@ class ASH_EXPORT AshDevToolsDOMAgent
       std::unique_ptr<ui::devtools::protocol::DOM::Node>* out_root) override;
 
   // WindowObserver
-  void OnWindowDestroying(WmWindow* window) override;
+  void OnWindowTreeChanging(WmWindow* window,
+                            const TreeChangeParams& params) override;
   void OnWindowTreeChanged(WmWindow* window,
                            const TreeChangeParams& params) override;
   void OnWindowStackingChanged(WmWindow* window) override;
@@ -38,7 +39,7 @@ class ASH_EXPORT AshDevToolsDOMAgent
       WmWindow* window);
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildInitialTree();
   void AddWindowNode(WmWindow* window);
-  void RemoveWindowNode(WmWindow* window, WmWindow* old_parent);
+  void RemoveWindowNode(WmWindow* window);
   void RemoveObserverFromAllWindows();
   void AddRootWindowObservers();
   void Reset();