Implement Drain() on HttpPipelinedStream.

net/http/http_response_body_drainer.cc

Index: net/http/http_response_body_drainer.cc
diff --git a/net/http/http_response_body_drainer.cc b/net/http/http_response_body_drainer.cc
index aefb18026528f2b90307349fc153e15cbdd7d3c6..f137c2419a50d504c299db14b73a4dc723dc59eb 100644
--- a/net/http/http_response_body_drainer.cc
+++ b/net/http/http_response_body_drainer.cc
@@ -25,7 +25,22 @@ HttpResponseBodyDrainer::HttpResponseBodyDrainer(HttpStream* stream)
 HttpResponseBodyDrainer::~HttpResponseBodyDrainer() {}
 
 void HttpResponseBodyDrainer::Start(HttpNetworkSession* session) {
-  read_buf_ = new IOBuffer(kDrainBodyBufferSize);
+  StartWithSize(session, kDrainBodyBufferSize);
+}
+
+void HttpResponseBodyDrainer::StartWithSize(HttpNetworkSession* session,
+                                            int num_bytes_to_drain) {
+  DCHECK_LE(0, num_bytes_to_drain);
+  if (num_bytes_to_drain > kDrainBodyBufferSize) {

[mmenke, 2011/11/28 18:39:10]

Just thinking out loud:  A larger minimum may be better for pipelined streams if
we've already sent another request over the wire.  Maybe be worth looking into,
at some point.  Fairly low priority, of course.

[James Simonsen, 2011/11/29 23:57:28]

Good point. I added a TODO.

+    Finish(ERR_RESPONSE_BODY_TOO_BIG_TO_DRAIN);
+    return;
+  } else if (num_bytes_to_drain == 0) {
+    Finish(OK);
+    return;
+  }
+
+  read_size_ = num_bytes_to_drain;
+  read_buf_ = new IOBuffer(read_size_);
   next_state_ = STATE_DRAIN_RESPONSE_BODY;
   int rv = DoLoop(OK);
 
@@ -71,7 +86,7 @@ int HttpResponseBodyDrainer::DoDrainResponseBody() {
   next_state_ = STATE_DRAIN_RESPONSE_BODY_COMPLETE;
 
   return stream_->ReadResponseBody(
-      read_buf_, kDrainBodyBufferSize - total_read_,
+      read_buf_, read_size_ - total_read_,
       &io_callback_);
 }