On iOS, detect pdp_ip networks as cellular.

BUG=
R=juberti@webrtc.org, tkchin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/44009004

Cr-Commit-Position: refs/heads/master@{#8943}
diff --git a/webrtc/base/network.cc b/webrtc/base/network.cc
index ff09236..2081c94 100644
--- a/webrtc/base/network.cc
+++ b/webrtc/base/network.cc
@@ -381,9 +381,15 @@
     if (existing_network == current_networks.end()) {
       AdapterType adapter_type = ADAPTER_TYPE_UNKNOWN;
       if (cursor->ifa_flags & IFF_LOOPBACK) {
-        // TODO(phoglund): Need to recognize other types as well.
         adapter_type = ADAPTER_TYPE_LOOPBACK;
       }
+#if defined(WEBRTC_IOS)
+      // Cell networks are pdp_ipN on iOS.
+      if (strncmp(cursor->ifa_name, "pdp_ip", 6) == 0) {
+        adapter_type = ADAPTER_TYPE_CELLULAR;
+      }
+#endif
+      // TODO(phoglund): Need to recognize other types as well.
       scoped_ptr<Network> network(new Network(cursor->ifa_name,
                                               cursor->ifa_name,
                                               prefix,