[Mac] Use CoreWLAN directly now that macOS 10.9 is the minimum version.

device/geolocation/wifi_data_provider_mac.h

Index: device/geolocation/wifi_data_provider_mac.h
diff --git a/device/geolocation/wifi_data_provider_mac.h b/device/geolocation/wifi_data_provider_mac.h
index 7d1f30bf59eda93cda810ae16d470df0d596f353..42f28984d56655f923727520957ef643d87cdab7 100644
--- a/device/geolocation/wifi_data_provider_mac.h
+++ b/device/geolocation/wifi_data_provider_mac.h
@@ -27,10 +27,6 @@ class WifiDataProviderMac : public WifiDataProviderCommon {
   DISALLOW_COPY_AND_ASSIGN(WifiDataProviderMac);
 };
 
-// Creates and returns a new API binding for the CoreWLAN API, or NULL if the
-// API can not be initialized.
-WifiDataProviderCommon::WlanApiInterface* NewCoreWlanApi();
-
 }  // namespace device
 
 #endif  // DEVICE_GEOLOCATION_WIFI_DATA_PROVIDER_MAC_H_