Remove unimplemented method

gfe-relnote: no behavior change, remove unimplemented method
PiperOrigin-RevId: 278939844
Change-Id: I7c45a443bef69c769d9e181cd28dfd4339e0ea7b

quic/tools/quic_memory_cache_backend.h

diff --git a/quic/tools/quic_memory_cache_backend.h b/quic/tools/quic_memory_cache_backend.h
index e0ff400..f88d458 100644
--- a/quic/tools/quic_memory_cache_backend.h
+++ b/quic/tools/quic_memory_cache_backend.h
@@ -134,9 +134,6 @@
   // 'response'.
   void AddDefaultResponse(QuicBackendResponse* response);
 
-  // |cache_cirectory| can be generated using `wget -p --save-headers <url>`.
-  void InitializeFromDirectory(const std::string& cache_directory);
-
   // Once called, URLs which have a numeric path will send a dynamically
   // generated response of that many bytes.
   void GenerateDynamicResponses();