Add Tether to Mobile NetworkTypePattern.

ash/system/network/network_icon.h

Index: ash/system/network/network_icon.h
diff --git a/ash/system/network/network_icon.h b/ash/system/network/network_icon.h
index 827cacc20695822eb2517cf962f69cf4b3f61c0a..a7b264032387f469aa276f6ac0741762f500361b 100644
--- a/ash/system/network/network_icon.h
+++ b/ash/system/network/network_icon.h
@@ -55,9 +55,9 @@ ASH_EXPORT base::string16 GetLabelForNetwork(
     const chromeos::NetworkState* network,
     IconType icon_type);
 
-// Updates and returns the appropriate message id if the cellular network
+// Updates and returns the appropriate message id if the mobile network
 // is uninitialized.
-ASH_EXPORT int GetCellularUninitializedMsg();
+ASH_EXPORT int GetMobileUninitializedMsg();
 
 // Gets the correct icon and label for |icon_type|. Also sets |animating|
 // based on whether or not the icon is animating (i.e. connecting).