Remove HTTP pipelining support.

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 e2784eed48366cb7e34ee1f03bd0229381a42135..09a2c1c859ee8e76a2317233ced965611842a960 100644
--- a/net/url_request/url_request.cc
+++ b/net/url_request/url_request.cc
@@ -82,9 +82,8 @@ bool g_default_can_use_cookies = true;
 // at which each event occurred.  The API requires the time which the request
 // was blocked on each phase.  This function handles the conversion.
 //
-// In the case of reusing a SPDY session or HTTP pipeline, old proxy results may
-// have been reused, so proxy resolution times may be before the request was
-// started.
+// In the case of reusing a SPDY session, old proxy results may have been
+// reused, so proxy resolution times may be before the request was started.
 //
 // Due to preconnect and late binding, it is also possible for the connection
 // attempt to start before a request has been started, or proxy resolution