SyncFS: Introduce SyncFileSystemBackend

webkit/browser/fileapi/file_system_backend.h

Index: webkit/browser/fileapi/file_system_backend.h
diff --git a/webkit/browser/fileapi/file_system_backend.h b/webkit/browser/fileapi/file_system_backend.h
index 37cb6b066b894b7a39930b4117f0e6d1335c3d7e..d4be4a824781fd0434e9a0d980c43a8f07aec28e 100644
--- a/webkit/browser/fileapi/file_system_backend.h
+++ b/webkit/browser/fileapi/file_system_backend.h
@@ -69,10 +69,14 @@ class WEBKIT_STORAGE_BROWSER_EXPORT FileSystemBackend {
   // Returns the specialized FileSystemFileUtil for this mount point.
   // It is ok to return NULL if the filesystem doesn't support synchronous
   // version of FileUtil.
-  virtual FileSystemFileUtil* GetFileUtil(FileSystemType type) = 0;
+  virtual FileSystemFileUtil* GetFileUtil(
+      FileSystemType type,
+      const FileSystemContext* context) = 0;
 
   // Returns the specialized AsyncFileUtil for this mount point.
-  virtual AsyncFileUtil* GetAsyncFileUtil(FileSystemType type) = 0;
+  virtual AsyncFileUtil* GetAsyncFileUtil(
+      FileSystemType type,
+      const FileSystemContext* context) = 0;
 
   // Returns the specialized CopyOrMoveFileValidatorFactory for this mount
   // point and |type|.  If |error_code| is PLATFORM_FILE_OK and the result