Move string.h to internal code
diff --git a/src/core/transport/chttp2_transport.c b/src/core/transport/chttp2_transport.c
index 17b37d6..6dfffa1 100644
--- a/src/core/transport/chttp2_transport.c
+++ b/src/core/transport/chttp2_transport.c
@@ -37,6 +37,7 @@
#include <stdio.h>
#include <string.h>
+#include "src/core/support/string.h"
#include "src/core/transport/chttp2/frame_data.h"
#include "src/core/transport/chttp2/frame_goaway.h"
#include "src/core/transport/chttp2/frame_ping.h"
@@ -53,7 +54,6 @@
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/slice_buffer.h>
-#include <grpc/support/string.h>
#include <grpc/support/useful.h>
#define DEFAULT_WINDOW 65535