Make URLFetcherFileWriter::Finish() skip closing file when there is an error

net/url_request/url_fetcher_response_writer.h

Index: net/url_request/url_fetcher_response_writer.h
diff --git a/net/url_request/url_fetcher_response_writer.h b/net/url_request/url_fetcher_response_writer.h
index f739502b9c9eb93e8d6d90bb40a10008dd163878..b65e27c9d2c63707ed69b577313ea6ad49dc08ff 100644
--- a/net/url_request/url_fetcher_response_writer.h
+++ b/net/url_request/url_fetcher_response_writer.h
@@ -45,9 +45,10 @@ class NET_EXPORT URLFetcherResponseWriter {
                     int num_bytes,
                     const CompletionCallback& callback) = 0;
 
-  // Finishes writing. If ERR_IO_PENDING is returned, |callback| will be run
+  // Finishes writing. If |net_error| is not OK, the writer might choose to skip
+  // graceful shutdown. If ERR_IO_PENDING is returned, |callback| will be run

[mmenke, 2016/10/19 14:32:29]

Also, think we should be more explicit that if net_error is not OK, this may be
called in the middle of another operation (We could actually wait for the write
to complete instead, but that gets complicated)

[xunjieli, 2016/10/19 15:19:28]

Done.

   // later with the result.
-  virtual int Finish(const CompletionCallback& callback) = 0;
+  virtual int Finish(int net_error, const CompletionCallback& callback) = 0;
 
   // Returns this instance's pointer as URLFetcherStringWriter when possible.
   virtual URLFetcherStringWriter* AsStringWriter();
@@ -69,7 +70,7 @@ class NET_EXPORT URLFetcherStringWriter : public URLFetcherResponseWriter {
   int Write(IOBuffer* buffer,
             int num_bytes,
             const CompletionCallback& callback) override;
-  int Finish(const CompletionCallback& callback) override;
+  int Finish(int net_error, const CompletionCallback& callback) override;
   URLFetcherStringWriter* AsStringWriter() override;
 
  private:
@@ -95,7 +96,7 @@ class NET_EXPORT URLFetcherFileWriter : public URLFetcherResponseWriter {
   int Write(IOBuffer* buffer,
             int num_bytes,
             const CompletionCallback& callback) override;
-  int Finish(const CompletionCallback& callback) override;
+  int Finish(int net_error, const CompletionCallback& callback) override;
   URLFetcherFileWriter* AsFileWriter() override;
 
   // Drops ownership of the file at |file_path_|.