Add CliCredentials, config_grpc_cli.h
diff --git a/test/cpp/util/grpc_cli.cc b/test/cpp/util/grpc_cli.cc
index 897ac5c..fe24860 100644
--- a/test/cpp/util/grpc_cli.cc
+++ b/test/cpp/util/grpc_cli.cc
@@ -40,7 +40,7 @@
       --protofiles=src/proto/grpc/testing/test.proto --enable_ssl=false
 
   Options:
-    1. --protofiles, use this flag to provide a proto file if the server does
+    1. --protofiles, use this flag to provide proto files if the server does
        does not have the reflection service.
     2. --proto_path, if your proto file is not under current working directory,
        use this flag to provide a search root. It should work similar to the
@@ -50,15 +50,17 @@
        --metadata="MyHeaderKey1:Value1:MyHeaderKey2:Value2"
     4. --enable_ssl, whether to use tls.
     5. --use_auth, if set to true, attach a GoogleDefaultCredentials to the call
-    6. --input_binary_file, a file containing the serialized request. The file
-       can be generated by calling something like:
+    6. --infile, input filename (defaults to stdin)
+    7. --outfile, output filename (defaults to stdout)
+    8. --binary_input, use the serialized request as input. The serialized
+       request can be generated by calling something like:
        protoc --proto_path=src/proto/grpc/testing/ \
          --encode=grpc.testing.SimpleRequest \
          src/proto/grpc/testing/messages.proto \
          < input.txt > input.bin
        If this is used and no proto file is provided in the argument list, the
        method string has to be exact in the form of /package.service/method.
-    7. --output_binary_file, a file to write binary format response into, it can
+    9. --binary_output, use binary format response as output, it can
        be later decoded using protoc:
        protoc --proto_path=src/proto/grpc/testing/ \
        --decode=grpc.testing.SimpleResponse \
@@ -72,6 +74,7 @@
 
 #include <gflags/gflags.h>
 #include <grpc++/support/config.h>
+#include "test/cpp/util/cli_credentials.h"
 #include "test/cpp/util/grpc_tool.h"
 #include "test/cpp/util/test_config.h"
 
@@ -93,6 +96,6 @@
   grpc::testing::InitTest(&argc, &argv, true);
 
   return grpc::testing::GrpcToolMainLib(
-      argc, (const char**)argv,
+      argc, (const char**)argv, grpc::testing::CliCredentials(),
       std::bind(SimplePrint, FLAGS_outfile, std::placeholders::_1));
 }