Move chrome.fileSystem implementation to //extensions

extensions/browser/api/file_system/saved_files_service_delegate.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 EXTENSIONS_BROWSER_API_FILE_SYSTEM_SAVED_FILES_SERVICE_DELEGATE_H_
+#define EXTENSIONS_BROWSER_API_FILE_SYSTEM_SAVED_FILES_SERVICE_DELEGATE_H_
+
+#include <string>
+
+#include "base/files/file_path.h"
+
+namespace extensions {
+namespace file_system_api {
+
+// TODO(michaelpg): These methods are abstracted into a delegate only because
+// any real implementation will be dependent on apps::SavedFilesService, which
+// the extensions module must not depend on. Ideally, the chrome.fileSystem API
+// itself would be implemented in //apps and we wouldn't have this problem.
+class SavedFilesServiceDelegate {
+ public:
+  // Basic information about a registered file.
+  struct File {
+    std::string id;
+    base::FilePath path;
+    bool is_directory;
+  };
+
+  virtual ~SavedFilesServiceDelegate(){};
+
+  // Returns whether the file with the given |id| has been registered.
+  virtual bool IsRegistered(const std::string& extension_id,
+                            const std::string& id) = 0;
+
+  // Registers a file with the saved files service.
+  virtual void RegisterFileEntry(const std::string& extension_id,
+                                 const File& file) = 0;
+
+  // If the file is registered, populates |file| with its information and
+  // returns true.
+  virtual bool GetRegisteredFileInfo(const std::string& extension_id,
+                                     const std::string& id,
+                                     File* file) = 0;
+
+  // Moves or adds |id| to the back of the queue of files to be retained.
+  virtual void EnqueueFileEntry(const std::string& extension_id,
+                                const std::string& id) = 0;
+};
+
+}  // namespace file_system_api
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_FILE_SYSTEM_SAVED_FILES_SERVICE_DELEGATE_H_