Use of base::StringPairs appropriately in net/disk_cache/memory

net/disk_cache/memory/mem_backend_impl.h

Index: net/disk_cache/memory/mem_backend_impl.h
diff --git a/net/disk_cache/memory/mem_backend_impl.h b/net/disk_cache/memory/mem_backend_impl.h
index 7b18ca06138c7f2f9b2a256473ca43cbfc5d64dd..6be8e946797326ed0e3ed1e4ba20791382eefccf 100644
--- a/net/disk_cache/memory/mem_backend_impl.h
+++ b/net/disk_cache/memory/mem_backend_impl.h
@@ -10,6 +10,7 @@
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/weak_ptr.h"
+#include "base/strings/string_split.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/memory/mem_rankings.h"
 
@@ -80,8 +81,7 @@ class NET_EXPORT_PRIVATE MemBackendImpl : public Backend {
   int DoomEntriesSince(base::Time initial_time,
                        const CompletionCallback& callback) override;
   scoped_ptr<Iterator> CreateIterator() override;
-  void GetStats(
-      std::vector<std::pair<std::string, std::string>>* stats) override {}
+  void GetStats(base::StringPairs* stats) override {}
   void OnExternalCacheHit(const std::string& key) override;
 
  private: