Merge pull request #13952 from vjpai/functional

Need to include functional to use std::bind

test/core/transport/chttp2/settings_timeout_test.cc

@@ -21,6 +21,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include <functional>
 #include <memory>
 #include <thread>