Use PreloadCheckGroup in ExtensionInstallChecker. Make RequirementsChecker a PreloadCheck.

chrome/browser/extensions/api/management/chrome_management_api_delegate.h

 // Copyright 2014 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_MANAGEMENT_CHROME_MANAGEMENT_API_DELEGATE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_MANAGEMENT_CHROME_MANAGEMENT_API_DELEGATE_H_
 
 #include "base/task/cancelable_task_tracker.h"
 #include "chrome/browser/extensions/extension_install_prompt.h"
 #include "chrome/browser/extensions/extension_uninstall_dialog.h"
@@ skipping 13 matching lines @@
       const extensions::ExtensionPrefs* prefs,
       const extensions::Extension* extension) const override;
   void GetPermissionWarningsByManifestFunctionDelegate(
       extensions::ManagementGetPermissionWarningsByManifestFunction* function,
       const std::string& manifest_str) const override;
   std::unique_ptr<extensions::InstallPromptDelegate> SetEnabledFunctionDelegate(
       content::WebContents* web_contents,
       content::BrowserContext* browser_context,
       const extensions::Extension* extension,
       const base::Callback<void(bool)>& callback) const override;
-  std::unique_ptr<extensions::RequirementsChecker> CreateRequirementsChecker()
-      const override;
   std::unique_ptr<extensions::UninstallDialogDelegate>
   UninstallFunctionDelegate(
       extensions::ManagementUninstallFunctionBase* function,
       const extensions::Extension* target_extension,
       bool show_programmatic_uninstall_ui) const override;
   bool CreateAppShortcutFunctionDelegate(
       extensions::ManagementCreateAppShortcutFunction* function,
       const extensions::Extension* extension,
       std::string* error) const override;
   std::unique_ptr<extensions::AppForLinkDelegate>
@@ skipping 18 matching lines @@
   void SetLaunchType(content::BrowserContext* context,
                      const std::string& extension_id,
                      extensions::LaunchType launch_type) const override;
   GURL GetIconURL(const extensions::Extension* extension,
                   int icon_size,
                   ExtensionIconSet::MatchType match,
                   bool grayscale) const override;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_MANAGEMENT_CHROME_MANAGEMENT_API_DELEGATE_H_