Refactor the UpdateEngine and its actions in the component updater.

components/update_client/action_wait.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_WAIT_H_
-#define COMPONENTS_UPDATE_CLIENT_ACTION_WAIT_H_
-
-#include "base/callback.h"
-#include "base/macros.h"
-#include "base/time/time.h"
-
-#include "components/update_client/action.h"
-
-namespace update_client {
-
-// Implements a wait between handling updates for the CRXs in this context.
-// To avoid thrashing of local computing resources, updates are applied one
-// at a time, with a delay between them.
-class ActionWait : public Action, protected ActionImpl {
- public:
-  explicit ActionWait(const base::TimeDelta& time_delta);
-  ~ActionWait() override;
-
-  void Run(UpdateContext* update_context, Callback callback) override;
-
- private:
-  void WaitComplete();
-
-  const base::TimeDelta time_delta_;
-
-  DISALLOW_COPY_AND_ASSIGN(ActionWait);
-};
-
-}  // namespace update_client
-
-#endif  // COMPONENTS_UPDATE_CLIENT_ACTION_WAIT_H_