Save pipelining capabilities for the most used hosts between sessions.

net/http/http_pipelined_host_capability.h

Index: net/http/http_pipelined_host_capability.h
diff --git a/net/http/http_pipelined_host_capability.h b/net/http/http_pipelined_host_capability.h
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index 0000000000000000000000000000000000000000..2c44cd363875680c1cfdf459809813c6f89fa22f
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+++ b/net/http/http_pipelined_host_capability.h
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+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_HTTP_HTTP_PIPELINED_HOST_CAPABILITY_H_
+#define NET_HTTP_HTTP_PIPELINED_HOST_CAPABILITY_H_
+#pragma once
+
+namespace net {
+
+// These values are serialized in Preferences. Do not change these values and
+// only add new ones at the end.
+enum HttpPipelinedHostCapability {
+  PIPELINE_UNKNOWN = 0,
+  PIPELINE_INCAPABLE = 1,
+  PIPELINE_CAPABLE = 2,
+  PIPELINE_PROBABLY_CAPABLE = 3,  // We are using pipelining, but haven't
+                                  // processed enough requests to record this
+                                  // host as known to be capable.
+};
+
+}  // namespace net
+
+#endif  // NET_HTTP_HTTP_PIPELINED_HOST_CAPABILITY_H_