Save device secret

Device secret is needed for verification of auth tokens after device
restart.

BUG: 24110921
Change-Id: If956886fcd6325dd4b419b7ca39ccb6bc4708230
Reviewed-on: https://weave-review.googlesource.com/1180
Reviewed-by: Alex Vakulenko <avakulenko@google.com>

libweave/src/privet/publisher.h

diff --git a/libweave/src/privet/publisher.h b/libweave/src/privet/publisher.h
index d330992..c1a9325 100644
--- a/libweave/src/privet/publisher.h
+++ b/libweave/src/privet/publisher.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include <base/macros.h>
 
@@ -43,13 +44,14 @@
   void ExposeService();
   void RemoveService();
 
-  bool is_publishing_{false};
   provider::DnsServiceDiscovery* dns_sd_{nullptr};
 
   const DeviceDelegate* device_{nullptr};
   const CloudDelegate* cloud_{nullptr};
   const WifiDelegate* wifi_{nullptr};
 
+  std::pair<uint16_t, std::vector<std::string>> published_;
+
   DISALLOW_COPY_AND_ASSIGN(Publisher);
 };