components: Cleanup class/struct fwd declarations

components/update_client/action.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 COMPONENTS_UPDATE_CLIENT_ACTION_H_
 #define COMPONENTS_UPDATE_CLIENT_ACTION_H_
 
 #include <stddef.h>
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "components/update_client/crx_update_item.h"
 #include "components/update_client/update_client.h"
 
 namespace update_client {
 
-class Configurator;
 enum class Error;
 struct CrxUpdateItem;
 struct UpdateContext;
 
 // Any update can be broken down as a sequence of discrete steps, such as
 // checking for updates, downloading patches, updating, and waiting between
 // successive updates. An action is the smallest unit of work executed by
 // the update engine.
 //
 // Defines an abstract interface for a unit of work, executed by the
@@ skipping 48 matching lines @@
   UpdateContext* update_context_;  // Not owned by this class.
   Callback callback_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ActionImpl);
 };
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_ACTION_H_