Add WifiPHYLayerProtocol to SystemProfile.

WifiPHYLayerProtocol characterizes the physical layer (PHY) protocol
of the current association with an 802.11 access point. It uses
the common nomenclature of referring to the IEEE 802.11 standard
amendment which introduced the protocol, i.e. a/b/g/n.

TBR=sky
BUG=174414

Review URL: https://codereview.chromium.org/12082090

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182231 0039d316-1c4b-4281-b951-d872f2087c98
9 files changed