Change interface of ClaimRootClientAuthToken and ConfirmAuthToken

Add RootClientTokenOwner argument to check if this owner can claim
device.
Add ErrorPtr to return error in privet response.

BUG=25766815

Change-Id: I508c934e23092514e37b1f4790f0f1e693583ae1
Reviewed-on: https://weave-review.googlesource.com/1939
Reviewed-by: Alex Vakulenko <avakulenko@google.com>
diff --git a/src/privet/auth_manager.h b/src/privet/auth_manager.h
index 62a1606..ce406ce 100644
--- a/src/privet/auth_manager.h
+++ b/src/privet/auth_manager.h
@@ -44,16 +44,17 @@
 
   base::Time Now() const;
 
-  std::vector<uint8_t> ClaimRootClientAuthToken(RootClientTokenOwner owner);
-  bool ConfirmAuthToken(const std::vector<uint8_t>& token);
+  std::vector<uint8_t> ClaimRootClientAuthToken(RootClientTokenOwner owner,
+                                                ErrorPtr* error);
+  bool ConfirmAuthToken(const std::vector<uint8_t>& token, ErrorPtr* error);
 
   std::vector<uint8_t> GetRootClientAuthToken() const;
   bool IsValidAuthToken(const std::vector<uint8_t>& token) const;
 
- private:
   void SetSecret(const std::vector<uint8_t>& secret,
                  RootClientTokenOwner owner);
 
+ private:
   Config* config_{nullptr};
   base::DefaultClock default_clock_;
   base::Clock* clock_{&default_clock_};