Helper functions in NetworkChangeNotifier related to WWAN use

net/base/network_change_notifier.h

Index: net/base/network_change_notifier.h
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index 731c305bebbf6279a0dd4e10d41488a3dbe4d3d4..ee0feb7e72969162a125cf570f4e168f4188e3cb 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -130,9 +130,14 @@ class NET_EXPORT NetworkChangeNotifier {
   // |false| is inconclusive; even if some link is up, it is uncertain
   // whether a particular connection attempt to a particular remote site
   // will be successfully.
-  static bool IsOffline() {
-    return GetConnectionType() == CONNECTION_NONE;
-  }
+  static bool IsOffline();
+
+  // Returns true if |type| is a cellular connection.
+  // Returns false if |type| is CONNECTION_UNKNOWN, and thus, depending on the
+  // implementation of GetConnectionType(), it is possible that
+  // IsConnectionCellular(GetConnectionType()) returns false even if the
+  // current connection is cellular.

[Ryan Sleevi, 2012/10/22 17:34:00]

I'm not sure this comment still fully captures the cases.

It suggests that CONNECTION_UNKNOWN is the only reason why IsConnectionCellular
would return a mismatch, but the other examples include things such as wifi
tethering / use of a mifi device, where the connection type is Wifi, but the
actual connection to the network is 3G.

Perhaps highlight that GetConnectionType/IsConnectionCellular refers only to the
devices current connection, and may not reflect the actual connection to the
network? I'm sure you can find a better way to word it.

[droger, 2012/10/22 17:41:06]

It seems to me that this discussion applies to the GetConnectionType() function
rather than to IsConnectionCellular().
That said, the point still holds -- I'll try to come up with a good comment.

+  static bool IsConnectionCellular(ConnectionType type);
 
   // Like Create(), but for use in tests.  The mock object doesn't monitor any
   // events, it merely rebroadcasts notifications when requested.