token-server: Delegation config import, validation and evaluation.

tokenserver/api/admin/v1/admin.proto

Index: tokenserver/api/admin/v1/admin.proto
diff --git a/tokenserver/api/admin/v1/admin.proto b/tokenserver/api/admin/v1/admin.proto
index 12a10d770a191e9ec12235b7914fecf7f237e683..1acdf771da12a7d10d63a05c0d55afaa21a1fb03 100644
--- a/tokenserver/api/admin/v1/admin.proto
+++ b/tokenserver/api/admin/v1/admin.proto
@@ -15,11 +15,20 @@ import "github.com/luci/luci-go/tokenserver/api/machine_token.proto";
 service Admin {
   // ImportCAConfigs makes the server read CA configs from luci-config.
   //
+  // This reads 'tokenserver.cfg' file.
+  //
   // Note that regularly configs are read in background each 5 min.
   // ImportCAConfigs can be used to force config reread immediately. It will
   // block until the configs are read.
   rpc ImportCAConfigs(google.protobuf.Empty) returns (ImportedConfigs);
 
+  // ImportDelegationConfigs makes the server read 'delegation.cfg' config.
+  //
+  // Note that regularly configs are read in background each 5 min.
+  // ImportDelegationConfigs can be used to force config reread immediately. It
+  // will block until the configs are read.
+  rpc ImportDelegationConfigs(google.protobuf.Empty) returns (ImportedConfigs);
+
   // InspectMachineToken decodes a machine token and verifies it is valid.
   //
   // It verifies the token was signed by a private key of the token server and