feat: preliminary support for //extensions (#17440)

shell/browser/extensions/atom_extension_system_factory.h

@@ -0,0 +1,41 @@
+// 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 SHELL_BROWSER_EXTENSIONS_ATOM_EXTENSION_SYSTEM_FACTORY_H_
+#define SHELL_BROWSER_EXTENSIONS_ATOM_EXTENSION_SYSTEM_FACTORY_H_
+
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "extensions/browser/extension_system_provider.h"
+
+namespace extensions {
+
+// A factory that provides AtomExtensionSystem.
+class AtomExtensionSystemFactory : public ExtensionSystemProvider {
+ public:
+  // ExtensionSystemProvider implementation:
+  ExtensionSystem* GetForBrowserContext(
+      content::BrowserContext* context) override;
+
+  static AtomExtensionSystemFactory* GetInstance();
+
+ private:
+  friend struct base::DefaultSingletonTraits<AtomExtensionSystemFactory>;
+
+  AtomExtensionSystemFactory();
+  ~AtomExtensionSystemFactory() override;
+
+  // BrowserContextKeyedServiceFactory implementation:
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* context) const override;
+  content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const override;
+  bool ServiceIsCreatedWithBrowserContext() const override;
+
+  DISALLOW_COPY_AND_ASSIGN(AtomExtensionSystemFactory);
+};
+
+}  // namespace extensions
+
+#endif  // SHELL_BROWSER_EXTENSIONS_ATOM_EXTENSION_SYSTEM_FACTORY_H_