Revert of aura: Require explicit ownership of the Env instance.

mandoline/ui/aura/aura_init.h

 // Copyright 2015 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 MANDOLINE_UI_AURA_AURA_INIT_H_
 #define MANDOLINE_UI_AURA_AURA_INIT_H_
 
 #include "ui/mojo/init/ui_init.h"
 
-namespace aura {
-class Env;
-}
-
 namespace mojo {
 class Shell;
 class View;
 }
 
 namespace mandoline {
 
 // Sets up necessary state for aura when run with the viewmanager.
 class AuraInit {
  public:
   AuraInit(mojo::View* root, mojo::Shell* shell);
   ~AuraInit();
 
  private:
   void InitializeResources(mojo::Shell* shell);
 
-  scoped_ptr<aura::Env> env_;
   ui::mojo::UIInit ui_init_;
 
   DISALLOW_COPY_AND_ASSIGN(AuraInit);
 };
 
 }  // namespace mandoline
 
 #endif  // MANDOLINE_UI_AURA_AURA_INIT_H_