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..405b45f9143c634de48f2824b82d006e110be4e3 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) {
@@ -833,12 +829,7 @@ 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);
+  stream_.reset();
 }
 
 void DriveURLRequestJob::NotifySuccess() {