shill: wimax: Listen to WiMaxManager.Device.StatusChanged signal.

Use the status signal to update the connection state of the WiMax
service appropriately. Also, make sure that WiMaxService is
disassociated from the carrier device if a connection can't be
initiated or if it's dropped.

BUG=chrome-os-partner:10010
TEST=unit tests
CQ-DEPEND=I29dcfe4915e6f2559d022c60353aa12358ef5966
CQ-DEPEND=I223eaf61894f74905c591e38590e5e0620d07be0

Change-Id: I5fe48f0cc84c066eb6a63dc5d347ac5f265b86b1
Reviewed-on: https://gerrit.chromium.org/gerrit/23879
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Ready: Ben Chan <benchan@chromium.org>
diff --git a/mock_wimax_service.h b/mock_wimax_service.h
index 42c5ff3..52d1453 100644
--- a/mock_wimax_service.h
+++ b/mock_wimax_service.h
@@ -23,6 +23,7 @@
   MOCK_METHOD1(Start, bool(WiMaxNetworkProxyInterface *proxy));
   MOCK_METHOD0(Stop, void());
   MOCK_CONST_METHOD0(IsStarted, bool());
+  MOCK_METHOD1(SetState, void(ConnectState state));
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockWiMaxService);