QUIC - Cache the connection type and connection description. Make the

net/quic/network_connection.h

+// Copyright 2015 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_QUIC_NETWORK_CONNECTION_H_
+#define NET_QUIC_NETWORK_CONNECTION_H_
+
+#include "base/basictypes.h"
+#include "net/base/net_export.h"
+#include "net/base/network_change_notifier.h"
+
+namespace net {
+
+namespace test {
+class NetworkConnectionPeer;
+}  // namespace test
+
+// This class returns the current network's connection description. It also
+// cache's the connection description to fix crbug.com/422516.
+class NET_EXPORT NetworkConnection
+    : public NetworkChangeNotifier::IPAddressObserver,
+      public NetworkChangeNotifier::ConnectionTypeObserver {
+ public:
+  NetworkConnection();
+  ~NetworkConnection() override {}
+
+  // Return a string equivalent of current connection type. If the
+  // connection type is CONNECTION_WIFI, then we'll tease out some
+  // details when we are on WiFi, and hopefully leave only ethernet
+  // (with no WiFi available) in the CONNECTION_UNKNOWN category.  This
+  // *might* err if there is both ethernet, as well as WiFi, where WiFi
+  // was not being used that much. Most platforms don't distinguish Wifi vs
+  // Etherenet, and call everything CONNECTION_UNKNOWN :-(.
+  const char* GetDescription();

[Ryan Hamilton, 2015/02/23 18:43:00]

Please comment on the lifetime/ownership of this value. namely, do client need
to copy this string in case the underlying network type changes?

[ramant (doing other things), 2015/02/23 19:50:18]

Done.

+
+  // It clears the cached connection_type_ and connection_description_.
+  void Clear();
+
+  // NetworkChangeNotifier::IPAddressObserver methods:
+  void OnIPAddressChanged() override;
+
+  // NetworkChangeNotifier::ConnectionTypeObserver methods:
+  void OnConnectionTypeChanged(
+      NetworkChangeNotifier::ConnectionType type) override;
+
+ private:
+  friend class test::NetworkConnectionPeer;
+
+  // Cache the connection_type and the connection description string to avoid
+  // calling expensive GetWifiPHYLayerProtocol() function.
+  NetworkChangeNotifier::ConnectionType connection_type_;
+  const char* connection_description_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkConnection);
+};
+
+}  // namespace net
+
+#endif  // NET_QUIC_NETWORK_CONNECTION_H_