Make DesktopFactoryOzone instances to respect --ozone-platform

ui/views/widget/desktop_aura/desktop_factory_ozone.h

 // Copyright 2013 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_FACTORY_OZONE_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_FACTORY_OZONE_H_
 
 #include "ui/views/views_export.h"
 
 namespace display {
@@ skipping 13 matching lines @@
 }
 
 class VIEWS_EXPORT DesktopFactoryOzone {
  public:
   DesktopFactoryOzone();
   virtual ~DesktopFactoryOzone();
 
   // Returns the instance.
   static DesktopFactoryOzone* GetInstance();
 
-  // Sets the implementation delegate. Ownership is retained by the caller.
-  static void SetInstance(DesktopFactoryOzone* impl);
-
   // Delegates implementation of DesktopWindowTreeHost::Create externally to
   // Ozone implementation.
   virtual DesktopWindowTreeHost* CreateWindowTreeHost(
       internal::NativeWidgetDelegate* native_widget_delegate,
       DesktopNativeWidgetAura* desktop_native_widget_aura) = 0;
 
   // Delegates implementation of DesktopScreen externally to
   // Ozone implementation.
   virtual display::Screen* CreateDesktopScreen() = 0;
 
  private:
   static DesktopFactoryOzone* impl_; // not owned
 };
 
 }  // namespace views
 
 #endif // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_FACTORY_OZONE_H_