Basic HTTP pipelining support

net/http/http_stream_factory.h

Index: net/http/http_stream_factory.h
diff --git a/net/http/http_stream_factory.h b/net/http/http_stream_factory.h
index a1b51680067a116af4676b47fc237e763f1dc066..b3d8c1038f03c9caecc3574f12d9812c839bdff9 100644
--- a/net/http/http_stream_factory.h
+++ b/net/http/http_stream_factory.h
@@ -24,6 +24,7 @@ class HostPortPair;
 class HttpAlternateProtocols;
 class HttpAuthController;
 class HttpNetworkSession;
+class HttpPipelinedHost;
 class HttpResponseInfo;
 class HttpStream;
 class ProxyInfo;
@@ -172,6 +173,11 @@ class NET_API HttpStreamFactory {
   virtual void AddTLSIntolerantServer(const HostPortPair& server) = 0;
   virtual bool IsTLSIntolerantServer(const HostPortPair& server) const = 0;
 
+  // Called when a HttpPipelinedHost has new capacity. Attempts to allocate any
+  // pending pipeline-capable requests to the host.
+  virtual void OnHttpPipelinedHostHasAdditionalCapacity(
+      HttpPipelinedHost* host) = 0;
+
   // Static settings
   static GURL ApplyHostMappingRules(const GURL& url, HostPortPair* endpoint);