net: Implement canceling of all async operations in FileStream.

chrome/browser/chromeos/gdata/drive_protocol_handler.cc

Index: chrome/browser/chromeos/gdata/drive_protocol_handler.cc
diff --git a/chrome/browser/chromeos/gdata/drive_protocol_handler.cc b/chrome/browser/chromeos/gdata/drive_protocol_handler.cc
index 0fdaf5e30da5c21b6c0fcb6126f5770cc294b6a2..f624a30c80ad878eadf1ca03103d5f0903f3aaac 100644
--- a/chrome/browser/chromeos/gdata/drive_protocol_handler.cc
+++ b/chrome/browser/chromeos/gdata/drive_protocol_handler.cc
@@ -79,10 +79,6 @@ std::string FixupMimeType(const std::string& type) {
   return type;
 }
 
-// Empty callback for net::FileStream::Close().
-void EmptyCompletionCallback(int) {
-}
-
 // Helper function that reads file size.
 void GetFileSizeOnBlockingPool(const FilePath& file_path,
                                int64* file_size) {
@@ -845,9 +841,6 @@ void DriveURLRequestJob::RecordBytesRead(int bytes_read) {
 void DriveURLRequestJob::CloseFileStream() {
   if (!stream_.get())
     return;
-  stream_->Close(base::Bind(&EmptyCompletionCallback));
-  // net::FileStream::Close blocks until stream is closed, so it's safe to
-  // release the pointer here.
   stream_.reset(NULL);
 }