Expose connection subtype from NetworkChangeNotifier

net/base/network_change_notifier.h

 // Copyright (c) 2012 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_BASE_NETWORK_CHANGE_NOTIFIER_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 258 matching lines @@
   // user won't be able to connect to remote sites. However, another return
   // value doesn't imply that the user will be able to connect to remote sites;
   // even if some link is up, it is uncertain whether a particular connection
   // attempt to a particular remote site will be successful.
   // The returned value only describes the connection currently used by the
   // device, and does not take into account other machines on the network. For
   // example, if the device is connected using Wifi to a 3G gateway to access
   // the internet, the connection type is CONNECTION_WIFI.
   static ConnectionType GetConnectionType();
 
+  // Returns the connection subtype of the network the client is connected to.

[pauljensen, 2017/03/24 18:38:58]

"the connection subtype of the network the client is connected to"->"the
device's current default active network connection's subtype"

[tbansal1, 2017/03/24 23:22:24]

Done.

+  // The returned value only describes the connection currently used by the
+  // device, and does not take into account other machines on the network. For
+  // example, if the device is connected using Wifi to a 3G gateway to access
+  // the internet, the connection type is CONNECTION_WIFI.

[pauljensen, 2017/03/24 18:38:58]

there is no sub-type for WiFi

[pauljensen, 2017/03/24 18:38:59]

The returned value only describes the connection currently used by the
device, and does not take into account other machines on the network. For
example, if the device is connected using Wifi to a 3G gateway to access the
internet, the connection type is CONNECTION_WIFI.
->
The returned value only describes the first-hop connection, for example if the
device is connected via WiFi to a 4G hotspot, the returned value will reflect
WiFi, not 4G.

(Also please make this same replacement on line 273, but use
CONNECTION_WIFI_there.)

[tbansal1, 2017/03/24 23:22:24]

Thanks, I am more interested in cellular. If it proves useful, I may work on
getting the subtype for WiFi, although IIRC, there are some issues there due to
Android permissions.

I have added one more statement to explain that this may return UNKNOWN more
frequently. Let me know if it needs to be reworded.

[tbansal1, 2017/03/24 23:22:24]

Done.

+  static ConnectionSubtype GetConnectionSubtype();
+
   // Sets |max_bandwidth_mbps| to a theoretical upper limit on download
   // bandwidth, potentially based on underlying connection type, signal
   // strength, or some other signal. If the network subtype is unknown then
   // |max_bandwidth_mbps| is set to +Infinity and if there is no network
   // connection then it is set to 0.0. The circumstances in which a more
   // specific value is given are: when an Android device is connected to a
   // cellular or WiFi network, and when a ChromeOS device is connected to a
   // cellular network. See the NetInfo spec for the mapping of
   // specific subtypes to bandwidth values: http://w3c.github.io/netinfo/.
   // |connection_type| is set to the current active default network's connection
@@ skipping 202 matching lines @@
   // TODO(szym): Retrieve AddressMap from NetworkState. http://crbug.com/144212
   virtual const internal::AddressTrackerLinux*
       GetAddressTrackerInternal() const;
 #endif
 
   // These are the actual implementations of the static queryable APIs.
   // See the description of the corresponding functions named without "Current".
   // Implementations must be thread-safe. Implementations must also be
   // cheap as they are called often.
   virtual ConnectionType GetCurrentConnectionType() const = 0;
+  virtual ConnectionSubtype GetCurrentConnectionSubtype() const;
   virtual void GetCurrentMaxBandwidthAndConnectionType(
       double* max_bandwidth_mbps,
       ConnectionType* connection_type) const;
   virtual bool AreNetworkHandlesCurrentlySupported() const;
   virtual void GetCurrentConnectedNetworks(NetworkList* network_list) const;
   virtual ConnectionType GetCurrentNetworkConnectionType(
       NetworkHandle network) const;
   virtual NetworkHandle GetCurrentDefaultNetwork() const;
 
   // Hook that allows derived implementations to log histograms at the time a
@@ skipping 62 matching lines @@
 
   // Set true to disable non-test notifications (to prevent flakes in tests).
   static bool test_notifications_only_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_H_