URLFetcher won't call delegate until file is closed.

net/base/file_stream_context.h

Index: net/base/file_stream_context.h
diff --git a/net/base/file_stream_context.h b/net/base/file_stream_context.h
index 15c25bb8d4a26cbfad355b0ec91e4f64c7ad5e0f..3ce8a5b6cdc9cb7decd553e50aa4cb05f66eac69 100644
--- a/net/base/file_stream_context.h
+++ b/net/base/file_stream_context.h
@@ -109,6 +109,8 @@ class FileStream::Context {
 
   void CloseSync();
 
+  void CloseAsync(const CompletionCallback& callback);
+
   void SeekAsync(Whence whence,
                  int64 offset,
                  const Int64CompletionCallback& callback);
@@ -191,6 +193,9 @@ class FileStream::Context {
   // Flushes all data written to the stream.
   IOResult FlushFileImpl();
 
+  // Closes the file.
+  IOResult CloseFileImpl();
+
 #if defined(OS_WIN)
   void IOCompletionIsPending(const CompletionCallback& callback, IOBuffer* buf);