IWYU: add string for std::string
diff --git a/ruy/profiler/instrumentation.h b/ruy/profiler/instrumentation.h
index c4df1e6..2b15ae3 100644
--- a/ruy/profiler/instrumentation.h
+++ b/ruy/profiler/instrumentation.h
@@ -19,6 +19,7 @@
 #ifdef RUY_PROFILER
 #include <cstdio>
 #include <mutex>
+#include <string>
 #include <vector>
 #endif