Implement Drain() on HttpPipelinedStream.

net/http/http_stream_parser.cc

Index: net/http/http_stream_parser.cc
diff --git a/net/http/http_stream_parser.cc b/net/http/http_stream_parser.cc
index 707e1ba67196bcd8fc7a05941b40f5f0bed369b8..5ee1f22700179d49d0f52daa00660b2beda9b33e 100644
--- a/net/http/http_stream_parser.cc
+++ b/net/http/http_stream_parser.cc
@@ -721,11 +721,8 @@ void HttpStreamParser::CalculateResponseBodySize() {
     response_body_length_ = 0;
 
   if (response_body_length_ == -1) {
-    // Ignore spurious chunked responses from HTTP/1.0 servers and
-    // proxies. Otherwise "Transfer-Encoding: chunked" trumps
-    // "Content-Length: N"
-    if (response_->headers->GetHttpVersion() >= HttpVersion(1, 1) &&
-        response_->headers->HasHeaderValue("Transfer-Encoding", "chunked")) {
+    // "Transfer-Encoding: chunked" trumps "Content-Length: N"
+    if (response_->headers->IsChunkEncoded()) {
       chunked_decoder_.reset(new HttpChunkedDecoder());
     } else {
       response_body_length_ = response_->headers->GetContentLength();