DesktopAura: Track windows "owned" via the DesktopWindowTreeHost

ui/views/widget/desktop_aura/desktop_window_tree_host.h

 // Copyright (c) 2012 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 UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_H_
 
 #include <memory>
 
 #include "ui/aura/window_event_dispatcher.h"
@@ skipping 149 matching lines @@
   virtual void SizeConstraintsChanged() = 0;
 
   // Returns true if the transparency of the DesktopNativeWidgetAura's
   // |content_window_| should change.
   virtual bool ShouldUpdateWindowTransparency() const = 0;
 
   // A return value of true indicates DesktopNativeCursorManager should be
   // used, a return value of false indicates the DesktopWindowTreeHost manages
   // cursors itself.
   virtual bool ShouldUseDesktopNativeCursorManager() const = 0;
+
+  // Returns a list of DesktopWindowTreeHost owned by |this|. That is, hosts
+  // that are automatically destroyed along with |this|.
+  virtual std::vector<DesktopWindowTreeHost*> GetOwnedTopLevelHosts() const = 0;
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_H_