Refactors StackingController::GetDefaultParent to ash/wm/common

ash/root_window_controller.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 ASH_ROOT_WINDOW_CONTROLLER_H_
 #define ASH_ROOT_WINDOW_CONTROLLER_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 77 matching lines @@
 
   // Creates and Initialize the RootWindowController for secondary displays.
   static void CreateForSecondaryDisplay(AshWindowTreeHost* host);
 
   // Returns a RootWindowController of the window's root window.
   static RootWindowController* ForWindow(const aura::Window* window);
 
   // Returns the RootWindowController of the target root window.
   static RootWindowController* ForTargetRootWindow();
 
-  // Returns container which contains a given |window|.
-  static aura::Window* GetContainerForWindow(aura::Window* window);
-
   ~RootWindowController() override;
 
   AshWindowTreeHost* ash_host() { return ash_host_.get(); }
   const AshWindowTreeHost* ash_host() const { return ash_host_.get(); }
 
   aura::WindowTreeHost* GetHost();
   const aura::WindowTreeHost* GetHost() const;
   aura::Window* GetRootWindow();
   const aura::Window* GetRootWindow() const;
 
@@ skipping 199 matching lines @@
 };
 
 
 // Gets the RootWindowController for |root_window|.
 ASH_EXPORT RootWindowController* GetRootWindowController(
     const aura::Window* root_window);
 
 }  // namespace ash
 
 #endif  // ASH_ROOT_WINDOW_CONTROLLER_H_