Add stats for network merge.

Currently, in ipc_network_manager.cc, the UMA WebRTC.PeerConnection.IPv4Interfaces and its IPv6
counter part counts the addresses, instead of the interfaces as when
chromium delivers available networks to WebRTC, each address is wrapped
inside an individual network object.

The plan is to replace the current MergeNetworkList with the new one once it's rolled into chromium.

BUG=
R=pthatcher@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/36779004

Cr-Commit-Position: refs/heads/master@{#8188}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8188 4adac7df-926f-26a2-2b94-8c16560cd09d
3 files changed