chrome: Cleanup class/struct forward declarations

chrome/browser/extensions/api/developer_private/developer_private_api.h

 // Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_DEVELOPER_PRIVATE_DEVELOPER_PRIVATE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DEVELOPER_PRIVATE_DEVELOPER_PRIVATE_API_H_
 
 #include <set>
 
 #include "base/files/file.h"
@@ skipping 24 matching lines @@
 #include "ui/shell_dialogs/select_file_dialog.h"
 
 class Profile;
 
 namespace extensions {
 
 class EventRouter;
 class ExtensionError;
 class ExtensionInfoGenerator;
 class ExtensionRegistry;
-class ExtensionSystem;
-class ManagementPolicy;
 class ProcessManager;
-class RequirementsChecker;
 
 namespace api {
 
-class EntryPicker;
 class EntryPickerClient;
 
 }  // namespace api
 
 class DeveloperPrivateEventRouter : public ExtensionRegistryObserver,
                                     public ErrorConsole::Observer,
                                     public ProcessManagerObserver,
                                     public AppWindowRegistry::Observer,
                                     public CommandService::Observer,
                                     public ExtensionActionAPI::Observer,
@@ skipping 545 matching lines @@
  protected:
   ~DeveloperPrivateUpdateExtensionCommandFunction() override;
   ResponseAction Run() override;
 };
 
 }  // namespace api
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DEVELOPER_PRIVATE_DEVELOPER_PRIVATE_API_H_