diff --git a/spdy/core/write_scheduler.h b/spdy/core/write_scheduler.h
index 98db442..c2c048f 100644
--- a/spdy/core/write_scheduler.h
+++ b/spdy/core/write_scheduler.h
@@ -6,12 +6,12 @@
 #define QUICHE_SPDY_CORE_WRITE_SCHEDULER_H_
 
 #include <cstdint>
+#include <string>
 #include <tuple>
 #include <vector>
 
 #include "net/third_party/quiche/src/spdy/core/spdy_protocol.h"
 #include "net/third_party/quiche/src/spdy/platform/api/spdy_export.h"
-#include "net/third_party/quiche/src/spdy/platform/api/spdy_string.h"
 
 namespace spdy {
 
@@ -154,7 +154,7 @@
   virtual size_t NumRegisteredStreams() const = 0;
 
   // Returns summary of internal state, for logging/debugging.
-  virtual SpdyString DebugString() const = 0;
+  virtual std::string DebugString() const = 0;
 };
 
 }  // namespace spdy