Removes aura dependencies from WindowPositioner

ash/wm/aura/wm_root_window_controller_aura.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_WM_AURA_WM_ROOT_CONTROLLER_AURA_H_
 #define ASH_WM_AURA_WM_ROOT_CONTROLLER_AURA_H_
 
 #include "ash/ash_export.h"
 #include "ash/wm/common/wm_root_window_controller.h"
 #include "base/macros.h"
@@ skipping 15 matching lines @@
   ~WmRootWindowControllerAura() override;
 
   static WmRootWindowControllerAura* Get(aura::Window* window) {
     return const_cast<WmRootWindowControllerAura*>(
         Get(const_cast<const aura::Window*>(window)));
   }
   static const WmRootWindowControllerAura* Get(const aura::Window* window);
 
   // WmRootWindowController:
   bool HasShelf() override;
+  WmGlobals* GetGlobals() override;
 
  private:
   RootWindowController* root_window_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(WmRootWindowControllerAura);
 };
 
 }  // namespace wm
 }  // namespace ash
 
 #endif  // ASH_WM_AURA_WM_ROOT_CONTROLLER_AURA_H_