Allow URLRequest::AppendChunkToUpload to take 0-byte final chunks.

net/url_request/url_request.cc

Index: net/url_request/url_request.cc
diff --git a/net/url_request/url_request.cc b/net/url_request/url_request.cc
index af06e3503b32c5b4a25d196798e5b2528268728d..d75a19c44899bd46f691970f57002448fba8c702 100644
--- a/net/url_request/url_request.cc
+++ b/net/url_request/url_request.cc
@@ -210,7 +210,6 @@ void URLRequest::AppendChunkToUpload(const char* bytes,
                                      bool is_last_chunk) {
   DCHECK(upload_data_stream_);
   DCHECK(upload_data_stream_->is_chunked());

[mmenke, 2015/02/11 19:43:56]

And one quick note...ChunkedUploadDataStream already has a bytes len can only be
0 for the final chunk DCHECK, so no reason to have it here.

-  DCHECK_GT(bytes_len, 0);
   upload_chunked_data_stream_->AppendData(bytes, bytes_len, is_last_chunk);
 }