net: Implement canceling of all async operations in FileStream.

chrome/browser/chromeos/drive/drive_protocol_handler.cc

Index: chrome/browser/chromeos/drive/drive_protocol_handler.cc
diff --git a/chrome/browser/chromeos/drive/drive_protocol_handler.cc b/chrome/browser/chromeos/drive/drive_protocol_handler.cc
index abf8a87668b78cf2dd3e73bbe2b33a96c72c8e3f..3a0ed79570f6a0e12776ad5951fd452509bbfcbf 100644
--- a/chrome/browser/chromeos/drive/drive_protocol_handler.cc
+++ b/chrome/browser/chromeos/drive/drive_protocol_handler.cc
@@ -77,10 +77,6 @@ std::string FixupMimeType(const std::string& type) {
   return type;
 }
 
-// Empty callback for net::FileStream::Close().
-void EmptyCompletionCallback(int) {
-}
-
 // Helper function that extracts and unescapes resource_id from drive urls
 // (drive:<resource_id>).
 bool ParseDriveUrl(const std::string& path, std::string* resource_id) {
@@ -835,9 +831,6 @@ 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);
 }