Add DriveFileSyncClient::IsAuthenticated

chrome/browser/sync_file_system/drive_file_sync_client.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_SYNC_FILE_SYSTEM_DRIVE_FILE_SYNC_CLIENT_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_FILE_SYNC_CLIENT_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
@@ skipping 118 matching lines @@
   // |remote_file_md5| represents the expected hash value of the file to be
   // updated on Drive. If |remote_file_md5| is different from the actual value,
   // cancels the upload and invokes |callback| with
   // GDataErrorCode::HTTP_CONFLICT immediately.
   void UploadExistingFile(const std::string& resource_id,
                           const std::string& remote_file_md5,
                           const FilePath& local_file_path,
                           int64 file_size,
                           const UploadFileCallback& callback);
 
+  // Returns true if the user is authenticated.
+  bool IsAuthenticated() const {
+    return drive_service_->HasRefreshToken();
+  }
+
   // Deletes the file identified by |resource_id|.
   // |remote_file_md5| represents the expected hash value of the file to be
   // deleted from Drive. If |remote_file_md5| is different from the actual
   // value, cancels the deletion and invokes |callback| with
   // GDataErrorCode::HTTP_CONFLICT immediately.
   void DeleteFile(const std::string& resource_id,
                   const std::string& remote_file_md5,
                   const GDataErrorCallback& callback);
 
  private:
@@ skipping 83 matching lines @@
 
   scoped_ptr<google_apis::DriveServiceInterface> drive_service_;
   scoped_ptr<google_apis::DriveUploaderInterface> drive_uploader_;
 
   DISALLOW_COPY_AND_ASSIGN(DriveFileSyncClient);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_FILE_SYNC_CLIENT_H_