Add GetURLForBrowserTab method to the external file system backend.

webkit/browser/fileapi/file_system_backend.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 WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_BACKEND_H_
 #define WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_BACKEND_H_
 
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "webkit/browser/fileapi/file_permission_policy.h"
 #include "webkit/browser/fileapi/open_file_system_mode.h"
 #include "webkit/browser/storage_browser_export.h"
 #include "webkit/common/fileapi/file_system_types.h"
 
 class GURL;
 
 namespace storage {
-class FileStreamReader;
-}
-
-namespace storage {
 
 class AsyncFileUtil;
 class CopyOrMoveFileValidatorFactory;
 class FileSystemURL;
+class FileStreamReader;
 class FileStreamWriter;
 class FileSystemContext;
 class FileSystemFileUtil;
 class FileSystemOperation;
 class FileSystemQuotaUtil;
 class WatcherManager;
 
+// Callback to take GURL.
+typedef base::Callback<void(const GURL& url)> URLCallback;
+
 // An interface for defining a file system backend.
 //
 // NOTE: when you implement a new FileSystemBackend for your own
 // FileSystem module, please contact to kinuko@chromium.org.
 //
 class STORAGE_EXPORT FileSystemBackend {
  public:
   // Callback for InitializeFileSystem.
   typedef base::Callback<void(const GURL& root_url,
                               const std::string& name,
@@ skipping 102 matching lines @@
   virtual void GrantFileAccessToExtension(
       const std::string& extension_id,
       const base::FilePath& virtual_path) = 0;
   // Revokes file access from extension identified with |extension_id|.
   virtual void RevokeAccessForExtension(
         const std::string& extension_id) = 0;
   // Gets virtual path by known filesystem path. Returns false when filesystem
   // path is not exposed by this provider.
   virtual bool GetVirtualPath(const base::FilePath& file_system_path,
                               base::FilePath* virtual_path) = 0;
+  // Gets a redirect URL for contents. e.g. Google Drive URL for hosted
+  // documents. Returns empty URL if the entry does not have the redirect URL.
+  virtual void GetRedirectURLForContents(
+      const storage::FileSystemURL& url,
+      const storage::URLCallback& callback) = 0;
 };
 
 }  // namespace storage
 
 #endif  // WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_BACKEND_H_