AddTo will return AddToTypeProxy for convenience

Change-Id: If86496af0c68af31a3e0c618b0fae861975a4ebf
Reviewed-on: https://weave-review.googlesource.com/2321
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
diff --git a/src/privet/auth_manager.cc b/src/privet/auth_manager.cc
index 0753a2b..66d04c4 100644
--- a/src/privet/auth_manager.cc
+++ b/src/privet/auth_manager.cc
@@ -65,14 +65,13 @@
                      ErrorPtr* error) {
   UwMacaroonCaveatType caveat_type{};
   if (!uw_macaroon_caveat_get_type_(&caveat, &caveat_type)) {
-    Error::AddTo(error, FROM_HERE, kInvalidTokenError, "Unable to get type");
-    return false;
+    return Error::AddTo(error, FROM_HERE, kInvalidTokenError,
+                        "Unable to get type");
   }
 
   if (caveat_type != type) {
-    Error::AddTo(error, FROM_HERE, kInvalidTokenError,
-                 "Unexpected caveat type");
-    return false;
+    return Error::AddTo(error, FROM_HERE, kInvalidTokenError,
+                        "Unexpected caveat type");
   }
 
   return true;
@@ -86,8 +85,8 @@
     return false;
 
   if (!uw_macaroon_caveat_get_value_uint_(&caveat, value)) {
-    Error::AddTo(error, FROM_HERE, kInvalidTokenError, "Unable to read caveat");
-    return false;
+    return Error::AddTo(error, FROM_HERE, kInvalidTokenError,
+                        "Unable to read caveat");
   }
 
   return true;
@@ -103,8 +102,8 @@
   const uint8_t* start{nullptr};
   size_t size{0};
   if (!uw_macaroon_caveat_get_value_str_(&caveat, &start, &size)) {
-    Error::AddTo(error, FROM_HERE, kInvalidTokenError, "Unable to read caveat");
-    return false;
+    return Error::AddTo(error, FROM_HERE, kInvalidTokenError,
+                        "Unable to read caveat");
   }
 
   value->assign(reinterpret_cast<const char*>(start), size);
@@ -144,8 +143,8 @@
   buffer->resize(kMaxMacaroonSize);
   if (!uw_macaroon_load_(token.data(), token.size(), buffer->data(),
                          buffer->size(), macaroon)) {
-    Error::AddTo(error, FROM_HERE, kInvalidTokenError, "Invalid token format");
-    return false;
+    return Error::AddTo(error, FROM_HERE, kInvalidTokenError,
+                        "Invalid token format");
   }
   return true;
 }
@@ -155,9 +154,8 @@
                     ErrorPtr* error) {
   CHECK_EQ(kSha256OutputSize, secret.size());
   if (!uw_macaroon_verify_(&macaroon, secret.data(), secret.size())) {
-    Error::AddTo(error, FROM_HERE, "invalid_signature",
-                 "Invalid token signature");
-    return false;
+    return Error::AddTo(error, FROM_HERE, "invalid_signature",
+                        "Invalid token signature");
   }
   return true;
 }
@@ -271,23 +269,20 @@
                   &user_id, error) ||
       !ReadCaveat(macaroon.caveats[2], kUwMacaroonCaveatTypeExpiration,
                   &expiration, error)) {
-    Error::AddTo(error, FROM_HERE, errors::kInvalidAuthorization,
-                 "Invalid token");
-    return false;
+    return Error::AddTo(error, FROM_HERE, errors::kInvalidAuthorization,
+                        "Invalid token");
   }
 
   AuthScope auth_scope{FromMacaroonScope(scope)};
   if (auth_scope == AuthScope::kNone) {
-    Error::AddTo(error, FROM_HERE, errors::kInvalidAuthorization,
-                 "Invalid token data");
-    return false;
+    return Error::AddTo(error, FROM_HERE, errors::kInvalidAuthorization,
+                        "Invalid token data");
   }
 
   base::Time time{base::Time::FromTimeT(expiration)};
   if (time < clock_->Now()) {
-    Error::AddTo(error, FROM_HERE, errors::kAuthorizationExpired,
-                 "Token is expired");
-    return false;
+    return Error::AddTo(error, FROM_HERE, errors::kAuthorizationExpired,
+                        "Token is expired");
   }
 
   if (user_info)
@@ -329,8 +324,7 @@
                      return auth.first->IsValidAuthToken(token, nullptr);
                    });
   if (claim == pending_claims_.end()) {
-    Error::AddTo(error, FROM_HERE, errors::kNotFound, "Unknown claim");
-    return false;
+    return Error::AddTo(error, FROM_HERE, errors::kNotFound, "Unknown claim");
   }
 
   SetAuthSecret(claim->first->GetAuthSecret(), claim->second);
@@ -358,8 +352,8 @@
   UwMacaroon macaroon{};
   if (!LoadMacaroon(token, &buffer, &macaroon, error) ||
       !VerifyMacaroon(auth_secret_, macaroon, error)) {
-    Error::AddTo(error, FROM_HERE, errors::kInvalidAuthCode, "Invalid token");
-    return false;
+    return Error::AddTo(error, FROM_HERE, errors::kInvalidAuthCode,
+                        "Invalid token");
   }
   return true;
 }