Fix dependencies on OutOfProcessPatcher.

components/update_client/component.h

 // Copyright 2017 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_COMPONENT_H_
 #define COMPONENTS_UPDATE_CLIENT_COMPONENT_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "base/version.h"
-#include "components/update_client/component_unpacker.h"
 #include "components/update_client/crx_downloader.h"
 #include "components/update_client/update_client.h"
 #include "components/update_client/update_response.h"
 #include "url/gurl.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace update_client {
 
 struct CrxUpdateItem;
+class ComponentUnpacker;
 struct UpdateContext;
 
 // Describes a CRX component managed by the UpdateEngine. Each |Component| is
 // associated with an UpdateContext.
 class Component {
  public:
   using Events = UpdateClient::Observer::Events;
 
   using CallbackHandleComplete = base::Callback<void()>;
 
@@ skipping 387 matching lines @@
   base::Closure update_check_complete_;
 
   DISALLOW_COPY_AND_ASSIGN(Component);
 };
 
 using IdToComponentPtrMap = std::map<std::string, std::unique_ptr<Component>>;
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_COMPONENT_H_