Introduce error handling in HttpStreamParser on UploadDataStream::Read() failure.

net/base/upload_data_stream.h

Index: net/base/upload_data_stream.h
diff --git a/net/base/upload_data_stream.h b/net/base/upload_data_stream.h
index fbfb32fee2680576de7b79209f8d595a305f4d1d..b3f360ef67f16bc83b2d1ad42185483d2d5bea41 100644
--- a/net/base/upload_data_stream.h
+++ b/net/base/upload_data_stream.h
@@ -56,9 +56,6 @@ class NET_EXPORT UploadDataStream {
   // upload data is smaller than size()), zeros are padded to ensure that
   // size() bytes can be read, which can happen for TYPE_FILE payloads.
   //
-  // Reads are currently not allowed to fail - they must either return
-  // a value >= 0 or ERR_IO_PENDING, and call OnReadCompleted with a
-  // value >= 0.
   // TODO(mmenke):  Investigate letting reads fail.
   int Read(IOBuffer* buf, int buf_len, const CompletionCallback& callback);