Client connectivity API

Initial plumbing work; needs tests and more client_channel
implementation.
diff --git a/src/core/channel/client_channel.h b/src/core/channel/client_channel.h
index fd2be46..16f1133 100644
--- a/src/core/channel/client_channel.h
+++ b/src/core/channel/client_channel.h
@@ -52,4 +52,11 @@
 void grpc_client_channel_set_resolver(grpc_channel_stack *channel_stack,
                                       grpc_resolver *resolver);
 
+grpc_connectivity_state grpc_client_channel_check_connectivity_state(
+    grpc_channel_element *elem, int try_to_connect);
+
+void grpc_client_channel_watch_connectivity_state(
+    grpc_channel_element *elem, grpc_connectivity_state *state,
+    grpc_iomgr_closure *on_complete);
+
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CLIENT_CHANNEL_H */