shill: add support for connecting to WPA-PSK networks

BUG=chromium-os:20897
TEST=unittests, some autotests (see below)

the following autotests now pass, at least in the wifi_vm_config:
- network_WiFiManager.000_SSID_Length_Limit
- network_WiFiSecMat.010CheckWPA_TKIP
- network_WiFiSecMat.011CheckWPA_AES
- network_WiFiSecMat.012CheckWPA_Multi
- network_WiFiSecMat.018CheckWPA_CounterMeasures

Change-Id: Ie7499fd87f661ceef3ef0aae348a08bd43c305f4
Reviewed-on: http://gerrit.chromium.org/gerrit/8586
Tested-by: mukesh agrawal <quiche@google.com>
Reviewed-by: Paul Stewart <pstew@chromium.org>
diff --git a/mock_wifi.h b/mock_wifi.h
index 9dc8430..fb3c428 100644
--- a/mock_wifi.h
+++ b/mock_wifi.h
@@ -36,6 +36,9 @@
   MOCK_METHOD1(Scan, void(Error *error));
   MOCK_METHOD2(GetService,
                WiFiServiceRefPtr(const KeyValueStore &args, Error *error));
+  MOCK_METHOD2(ConnectTo,
+               void(WiFiService *,
+                    const std::map<std::string, ::DBus::Variant> &));
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockWiFi);