Make extensions developer mode adhere to policy

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 104 matching lines @@
   void OnExtensionDisableReasonsChanged(const std::string& extension_id,
                                         int disable_reasons) override;
 
   // ExtensionManagement::Observer:
   void OnExtensionManagementSettingsChanged() override;
 
   // WarningService::Observer:
   void ExtensionWarningsChanged(
       const ExtensionIdSet& affected_extensions) override;
 
-  // Handles a profile preferance change.
+  // Handles a profile preference change.
   void OnProfilePrefChanged();
 
+  // Handles a change of the kDevToolsDisabled preference
+  void OnDevToolsDisabledChanged();
+
   // Broadcasts an event to all listeners.
   void BroadcastItemStateChanged(api::developer_private::EventType event_type,
                                  const std::string& id);
   void BroadcastItemStateChangedHelper(
       api::developer_private::EventType event_type,
       const std::string& extension_id,
       std::unique_ptr<ExtensionInfoGenerator> info_generator,
       std::vector<api::developer_private::ExtensionInfo> infos);
 
   ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
@@ skipping 470 matching lines @@
  protected:
   ~DeveloperPrivateUpdateExtensionCommandFunction() override;
   ResponseAction Run() override;
 };
 
 }  // namespace api
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DEVELOPER_PRIVATE_DEVELOPER_PRIVATE_API_H_